#include <stdio.h>     // Header

int main()                 // Main
{ 

    int a = 10           // Variable Declaration

    printf("%d", a);           // Body

    return 0;            // Return
} 

#include <stdio.h>
int main(void)
{ 
    printf("Hello Word"); 
    return 0; 
} 

Output : Hello Word

#include <stdio.h>
int main()
{
    int number = 25;
    int Number = 47;
    printf("The number is %d ",number);
    printf("\nThe Number is %d ",Number);
    return 0;
}

Output : The number is 25
         The Number is 47

#include <stdio.h>
int main()
{
    char a = 'b';
    printf("The character of a = %c ",a);
    return 0;
}

Output : The character of a = b

#include <stdio.h>
int main()
{
    int a = 8;
    printf("The value of a = %d ",a);
    return 0;
}

Output : The value of a = 8

#include <stdio.h>
int main()
{
    float a = 8.987654321;
    printf("The value of a = %0.9f",a);
    return 0;
}

Output : The value of a = 8.987654686

#include <stdio.h>
int main()
{
    double a = 8.987654321;
    printf("The value of a = %lf",a);
    return 0;
}

Output : The value of a = 8.987654321

#include <stdio.h>
int main()
{
    int a = 5;
    int b = 2;
    int l = a + b;
    int m = a - b;
    int n = a * b;
    int o = a / b;
    int p = a % b;
    printf("Addition of a and b = %d ", l);
    printf("\nSubtraction of a and b = %d ", m);
    printf("\nMultiplication of a and b = %d ", n);
    printf("\nDivision of a and b = %d ", o);
    printf("\nRemainder of a and b = %d ", p);
    return 0;
}

Output : Addition of a and b = 7
         Subtraction of a and b = 3
         Multiplication of a and b = 10
         Division of a and b = 2
         Remainder of a and b = 1

#include <stdio.h>
int main()
{
    int x = -5;
    int y = -x;
    printf("The value of x = %d \nThe value of y = %d ",x, y);
    return 0;
}

Output : The value of x = - 5
         The value of y = 5

#include <stdio.h>
int main()
{
    int a = 2;
    printf("The value of a = %d ", a);
    a = ++a;
    printf("\nThe value of a = %d ", a);
    return 0;
}

Output : The value of a = 2
         The value of a = 3

#include <stdio.h>
int main()
{
    int a = 2;
    printf("The value of a = %d ",a);
    a = --a;
    printf("\nThe value of a = %d ",a);
    return 0;
}

Output : The value of a = 2
         The value of a = 1

#include <stdio.h>
int main()
{
    int n = 10;
    printf("The value of n = %d ",n);
    printf("\nAddress of n = %u ",&n);
    return 0;
}

Output : The value of n = 10
         Address of n = 2293436

#include <stdio.h>
int main()
{
    int x = 5;
    float y = 10;
    printf("sizeof (x) = %d \nsizeof (y) = %d ",sizeof(x), sizeof(y));
    return 0;
}

Output : sizeof (x) = 2
         sizeof (y) = 4

#include <stdio.h>
int main()
{
    printf("\nCond.\t Return"); //Cond. stands for Condition
    printf("\n5 > 3  :\t %d",5 > 3);
    printf("\n5 < 3  :\t %d",5 < 3);
    printf("\n5 <= 5 :\t %d",5 >=5);
    printf("\n6 >= 5 :\t %d",6 >=5);
    printf("\n5 == 3 :\t %d",5 == 3);
    printf("\n3 != 3 :\t %d",3 != 3);
    return 0;
}

Output : Cond.     Return
         5 > 3  :   1
         5 < 3  :   0
         5 <= 5 :   1
         6 >= 5 :   1
         5 == 3 :   0
         5 == 3 :   0

#include <stdio.h>
int main()
{
    int a = 5;
    int b = 10;
    if(a < b)
        printf("a is the smallest number");
    else
        printf("b is the smallest number");
    return 0;
}

Output : a is the smallest number

#include <stdio.h>
int main()
{
    int a = 20;
    int b = 10;
    int c = 15;
    if(a < b && b < c)
        printf(" C is the greatest number of all");
    else
        printf(" C is not greatest number of all");
    return 0;
}

Output : C is not greatest number of all

#include <stdio.h>
int main()
{
    int a = 20;
    int b = 10;
    int c = 15;
    if(c>a || c>b)
         printf(" C is not smallest and may not biggest of all ");
    else
         printf(" C is smallest of all");
    return 0;
}

Output : C is not smallest and may not biggest of all

#include <stdio.h>
int main()
{
    int a = 20;
    int b = 10;
    if(a != b )
        printf("a is not equal to b");
    else
        printf(" a is equal to b");
    return 0;
}

Output : a is not equal to b

#include <stdio.h>
int main()
{
    int a = 10, b = 2;
    printf("a & b = %d ", a & b);
    return 0;
}

Output : a & b = 2

#include <stdio.h>
int main()
{
    int a = 10, b = 2;
    printf("a | b = %d ", a | b);
    return 0;
}

Output : a | b = 10

#include <stdio.h>
int main()
{
    int a = 10, b = 2;
    printf("a ^ b = %d ", a ^ b);
    return 0;
}

Output : a ^ b = 8

#include <stdio.h>
int main()
{
    int a = 8,b;
    a>>= 1;
    b = a;
    printf("The Right shifted data of 8 by 1 = %d ",b);
    return 0;
}

Output : The Right shifted data of 8 by 1 = 4

#include <stdio.h>
int main()
{
    int a = 4, b;
    a<<= 1;
    b = a;
    printf("The Left shifted data of 4 by 1 = %d ",b);
    return 0;
}

Output : The Left shifted data of 4 by 1 = 8

#include <stdio.h>
int main()
{
    unsigned short int a = 10;
    a = ~a;
    printf("After One's Complement a = %u", a);
    return 0;
}

Output : After One's Complement a = 65525

#include <stdio.h>
int main()
{
    int son = 18;
    int father = 40;
    int younger_age;
    younger_age = son < father ? son : father;
    printf("%d is the younger age", younger_age);
    return 0;
}

Output : 18 is the younger age

#include <stdio.h>  //header file section
int value();        // function declaration
int a = 7;          //variable a is declared globally
int main()
{
    value();           //calling a function
    return 0;
}
int value()
{
    int a = 5;
    printf("The value of a = %d ",a);
    printf("\nThe value of a = %d ",::a);
    return 0;
}

Output : The value of a = 5
         The value of a = 7

#include <stdio.h>  //header file section
int main()
{
    int a, b, c;
    printf("Enter the value of a = ");
    scanf("%d",&a) ;             //read value a through keyboard
    printf("\nEnter the value of b = ");
    scanf("%d",&b);              //read value b through keyboard
    c = a + b;
    printf("\na + b = %d ",c);   //Print the sum of two value a and b
    return 0;
}

Output : Enter the value of a = 6
         Enter the value of b = 4
         a + b = 10

#include <stdio.h>  //header file section
int main()
{
    float a, b, c, d;
    printf("Enter three float numbers:\n ");
    scanf("\n %f %f %f ",&a,&b,&c);
    d = (a + b + c)/3;
    printf("\nAverage of given number is %f ",d);
    return 0;
}

Output : Enter three float numbers:
         4.5
         4.5
         5.0
         Average of given number is 4.666667

#include <stdio.h>  //header file section
#include <conio.h> 
int main()
{
    char c;
    printf("Enter a character : ");
    c = getchar();
    printf("\nEntered character : %c ", c);
    return 0;
}

Output : Enter a character : y
         Entered character : y

#include <stdio.h>  //header file section
#include <conio.h>
int main()
{
    printf("\nHello, press any alphanumeric character to exit ");
    getch();
    return 0;
}

Output : Hello, press any alphanumeric character to exit

#include <stdio.h>  //header file section
#include <conio.h>
int main()
{
    printf("\nHello, press any alphanumeric character or symbol to exit \n ");
    getche();
    return 0;
}

Output : Hello, press any alphanumeric character or symbol to exit
         k

#include <stdio.h>  //header file section
#include <conio.h>
int main()
{
    char c = 'K';
    putchar(c);
    return 0;
}

Output : K

#include <stdio.h>  //header file section
#include <conio.h>
int main()
{
    char c;
    printf("Press any key to continue\n ");
    c = getch();
    printf("input : ");
    putch(c);
    return 0;
}

Output : Press any key to continue
         input : d 

#include <stdio.h>  //header file section
#include <conio.h>
int main()
{
    char c[25];
    printf("Enter a string : ");
    gets(c);
    printf("\n%s is awesome ",c);
    return 0;
}

Output : Enter a string : Randy Orton
         Randy Orton is awesome

#include <stdio.h>  //header file section
#include <conio.h>
int main()
{
    char c[25];
    printf("Enter your Name : ");
    gets(c);
    puts(c);
    return 0;
}

Output : Enter your Name: john
         john

#include <stdio.h>  //header file section
#include <conio.h>  
int main()
{
    int age = 18;
    if(age > 17)
    {
        printf("you are eligible for voting ");
    }
    printf("\nThis is normal flow ");
    return 0;
}

Output : you are eligible for voting
         This is normal flow

#include <stdio.h>  //header file section
int main()
{
    int age;
    printf("Enter your age : ");
    scanf("%d",&age);
    if(age > 17)
    {
        printf("\nyou are eligible for voting ");
    }
    else
    {
        printf("\nSorry, you are not eligible for voting ");
    }
    printf("\nThis is normal flow ");
    return 0;
}

Output : Enter your age : 16
         Sorry, you are not eligible for voting
         This is normal flow

#include <stdio.h>  //header file section
int main()
{
    int a = 47, b = 25, c = 3;
    if (a > b)
    {
        if (a > c)
        {
             printf("The value a is greater than b and c ");
        }
    }
    printf("\nThis is normal flow ");
    return 0;
}

Output : The value a is greater than b and c
         This is normal flow

#include <stdio.h>  //header file section
int main()
{
    int a;
    printf("Enter a number: ");
    scanf ("%d ", &a);
    if(a > 0)
    {
        printf("\n%d is a positive number", a);
    }
    else if(a < 0)
    {
        printf("\n%d is a negative number", a);
    }
    else
    {
        printf("\n%d is a zero",a);
    }
    return 0;
}

Output : Enter a number: -47
         -47 is a negative number

#include <stdio.h>  //header file section
int main()
{
    int choice;
    printf("Press 1 to greet your dad\n ");
    printf("Press 2 to greet your mom\n ");
    printf("Press 3 to greet yourself\n ");
    scanf("%d ",&choice);
    switch (choice)
    {
        case 1:
            printf("\nHello dad,How are you? ");
        break;
        case 2:
             printf("\nHello mom,How are you? ");
        break;
        case 3:
             printf("\nHello awesome,How are you? ");
        break;
        default:
             printf("\nInvalid choice ");
    }
    return 0;
}

Output : Press 1 to greet your dad
         Press 2 to greet your mom
         Press 3 to greet yourself
         1
         Hello dad,How are you?

#include <stdio.h>  //header file section
int main()
{
    int a;
    for(a = 1;a <= 5;a++)
    {
        printf("%d ",a);
    }
    return 0;
}

Output : 1 2 3 4 5

#include <stdio.h>  //header file section
int main()
{
    int a = 1;
    while(a <= 5)
    {
        printf("%d ", a);
        a++;
    }
    return 0;
}

Output : 1 2 3 4 5

#include <stdio.h>  //header file section
int main()
{
    do
    {
        printf("I will display once ");
    }
    while(2 > 10);
    return 0;
}


Output : I will display once

#include <stdio.h>  //header file section
int main()
{
    int a, b;
    for(a = 1; a <= 5; a++)
    {
        for(b = 1; b <= 5; b++)
        {
            printf("%d ", b);
        }
        printf("\n");
    }
    return 0;
}

Output : 1 2 3 4 5
         1 2 3 4 5
         1 2 3 4 5
         1 2 3 4 5
         1 2 3 4 5

#include <stdio.h>  //header file section
int main()
{
    int a = 1, b = 1;
    while(a <= 5)
    {
        b = 1;
        while(b <= 5)
        {
            printf("%d ", b);
            b++;
        }
        printf("\n");
        a++;
    }
    return 0;
}

Output : 1 2 3 4 5
         1 2 3 4 5
         1 2 3 4 5
         1 2 3 4 5
         1 2 3 4 5

#include <stdio.h>  //header file section
int main()
{
    do
    {
        printf("I'm from outer do-while loop ");
        do
        {
            printf("\nI'm from inner do-while loop ");
        }
        while(1 > 10);
    }
    while(2 > 10);
    return 0;
}

Output : I'm from outer do-while loop
         I'm from inner do-while loop

#include <stdio.h>
int main()
{
    int a;
    for(a = 1;a <= 5;a++)
    {
        if(a == 4)
        {
            break;
        }
        printf("%d ", a);
    }
    return 0;
}

Output : 1 2 3

#include <stdio.h>
int main()
{
    int a;
    for(a = 1;a <= 5; a++)
    {
        if(a == 4)
        {
            continue;
        }
        printf("%d", a);
    }
    return 0;
}

Output : 1 2 3 5

#include <stdio.h>
int main()
{
    int num;
    printf("Enter a positive or negative integer number:\n ");
    scanf("%d",&num);
    if(num >= 0)
        goto pos;
    else
        goto neg;
    pos:
    {
        printf("%d is a positive number",num);
        return 0;
    }
    neg:
    {
        printf("%d is a negative number",num);
        return 0;
    }
}

Output : Enter a positive or negative integer number:
         2
         2 is a positive number

#include <stdio.h>
int main()
{
    //main function definition
    int a = 5, b = 10;
    int sum;
    printf("The value of a and b : %d %d ", a, b);
    sum = add(a, b);    //function call
    printf("\nsum = %d ", sum);
}

//function definition
int add(int a, int b)
{
    int c;
    c = a + b;
    return c;    //returns a integer value to the calling function
}

Output : The value of a and b : 5 10
         sum = 15

#include <stdio.h>
void add();     //function declaration
int main()
{
    //main function definition
    add();    //function call without passing arguments
}

//function definition
void add()
{
    int a = 5, b = 10;
    int c;
    printf(" The values of a and b : %d %d ", a, b);
    c = a + b;
    printf(" \nsum : %d ", c);
    //no return values to the calling function
}

Output : The values of a and b : 5 10
         sum = 15

#include <stdio.h>
void add(int,int);     //function declaration
int main()
{
    //main function definition
    int sum;
    int a = 5, b = 10;
    printf(" The values of a and b : %d %d ", a, b);
    add( a, b);    //function call with passing arguments to called function
}

    // function definition
void add(int a, int b)
{
    int c;
    c = a + b;
    printf(" \nsum : %d ", c);
    //no return values to the calling function main
}

Output : The values of a and b : 5 10
         sum = 15

#include <stdio.h>
int add();     //function declaration
int main()
{
    //main function definition
    int sum;
    sum = add();    //function call without passing arguments to called function
    printf(" \nsum = %d ", sum);
}

// function definition
int add()
{
    int c;
    int a = 5, b = 10;
    printf(" The values of a and b : %d %d ", a, b);
    c = a + b;
    return c;    //passing return values to the calling function main
}

Output : The values of a and b : 5 10
         sum = 15

#include <stdio.h>
int add(int, int);     //function declaration
int main()
{
    //main function definition
    int sum;
    int a = 5, b = 10;
    printf(" The values of a and b : %d %d ", a, b);
    sum = add( a, b);    //function call with passing arguments
    printf(" \nsum = %d ", sum);
}

    // function definition
int add(int a, int b)
{
    int c;
    c = a + b;
    return c;    //passing return values to the calling function main
}

Output : The values of a and b : 5 10
         sum = 15

#include <stdio.h>
int rec(int count);     //function declaration
int main()
{
    rec(1);
    return 0;
}

int rec(int count)
{
    if(count > 5)
    {
        return 0;
    }
    else
    {
        printf("\nThis is recursion");
        count++;
        rec(count);
    }
    return 0;
}

Output : This is recursion
         This is recursion
         This is recursion
         This is recursion
         This is recursion

#include <stdio.h>
int pass(int, int);     //function declaration
int main()
{
    //main function definition
    int a = 5, b = 10;
    printf("The values of a and b in main function before function call : %d %d ", a, b);
    pass(a, b);    //function call with passing arguments as values
    printf("\nThe values of a and b in main function after function call : %d %d ", a, b);
}

// function definition
int pass(int a, int b)
{
    a = 10; b = 5;     //This change will not affect the actual parameters
    printf("\nThe values of a and b in called function : %d %d ", a, b);
}

Output : The values of a and b in main function before function call : 5 10
         The values of a and b in called function : 10 5
         The values of a and b in main function after function call : 5 10

#include <stdio.h>
int pass(int*, int*);     //function declaration
int main()
{
    //main function definition
    int a = 5, b = 10;
    printf("The values of a and b in main function before function call : %d %d ", a, b);
    pass(&a, &b);    //function call with passing arguments as addresses
    printf("\nThe values of a and b in main function after function call : %d %d ", a, b);
}

// function definition
int pass(int * a, int *b)
{
    *a = 10; *b = 5;     //This change will affect the actual parameters
    printf("\nThe values of a and b in called function : %d %d ",*a, *b);
}

Output : The values of a and b in main function before function call : 5 10
         The values of a and b in called function : 10 5
         The values of a and b in main function after function call : 10 5

#include <stdio.h>
int main()
{
    int s[5], i;
    printf ("Enter students marks details ");
    for(i = 0; i < 5; i++)
    {
        printf ("\ns%d = ", i + 1);
        scanf ("%d",&s[i]);
    }
    printf ("\n---Students marks details--- ");
    for(i = 0; i < 5; i++)
    {
        printf ("\ns%d = %d ", i + 1, s[i]);
    }
    return 0;
}

Output : Enter students marks details
         s1 = 78
         s2 = 90
         s3 = 87
         s4 = 92
         s5 = 95
         ---Students marks details---
         s1 = 78
         s2 = 90
         s3 = 87
         s4 = 92
         s5 = 95

#include <stdio.h>
int main()
{
    int s[5] = {89, 76, 98, 91, 84}, i;
    printf("\n---Students marks details--- ");
    for(i = 0; i < 5; i++)
    {
        printf("\ns%d = %d ", i + 1, s[i]);
    }
    return 0;
}

Output : ---Students marks details---
         s1 = 89
         s2 = 76
         s3 = 98
         s4 = 91
         s5 = 84

#include <stdio.h>
int main()
{
    int matrix[3][3] = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}, i, j;
    for(i = 0; i < 3; i++)
    {
        for(j = 0; j < 3; j++)
        {
            printf("%2d ", matrix[i] [j]);
        }
        printf("\n");
    }
    return 0;
}

Output : 1 2 3
         4 5 6
         7 8 9

#include <stdio.h>
#include <string.h>
int main()
{
char arr[3][10] = {"INDIA", "AMERICA", "JAPAN"};
printf("%s \n %s \n %s ", arr[0], arr[1], arr[2]);
return 0;
}

Output : INDIA
         AMERICA
         JAPAN

#include <stdio.h>
#include <string.h>
int main()
{
    char *arr[3] ;
    arr[0] = "INDIA";
    arr[1] = "AMERICA";
    arr[2] = "JAPAN";
    printf("%s \n %s \n %s ", arr[0], arr[1], arr[2]);
    return 0;
}

Output : INDIA
         AMERICA
         JAPAN

#include <stdio.h>
int main()
{
    //Structure Declaration
    struct student {
    char name[30];
    int rollno;
    float average;
};
//Structure Variable Declaration and Initialization
struct student record1 = {"Siva", 43, 76.54};
printf("\nStudent Name : %s", record1.name);
printf("\nStudent RollNo : %d ", record1.rollno);
printf("\nStudent Average: %d ", record1.average);
return 0;
}

Output : Student Name : Siva
         Student RollNo : 43
         Student Average: 76.73

#include <stdio.h>
int main()
{
//structures declartion
struct sample{
    double d1;     //occupies 8 bytes in memory
    float f1;     //occupies 4 bytes in memory
}s1;
//Union declartion
union samp{
    double d2;     //occupies 8 bytes in memory
    float f2;     //occupies 4 bytes in memory
}u1;
printf("\nSize of Structure : %d ", sizeof(s1));
printf("\nSize of Union : %d ", sizeof(u1));
return 0;
}

Output : Size of Structure : 16
         Size of Union : 8

#include <stdio.h>
int main()
{
/structures declartion
struct sample{
    int a;
    int b;
}s1;
//Union declartion
union samp{
    int c;
    int d;
}u1;
s1.a = 10;
s1.b = 20;
printf("\nThe Structure member values a and b are : %d %d ", s1. a, s1.b);
u1.c = 30;
u1.d = 40;
printf("\nThe Union member values c and d are : %d %d ", u1. c, u1.d);
return 0;
}

Output : The Structure member values a and b are : 10 20
         The Union member values c and d are : 40 40

#include <stdio.h>
int main()
{
    for(int i=1;i<=100;i++)
    {   
        // if number module i is equal to 0, then number is even
        if(i%2==0)
        {
            printf("%d\n", i);    
        }
    }
    return 0;
}

#include <stdio.h>
int main()
{
  int x, y, t;
 
  printf("Enter two integers\n");
  scanf("%d%d", &x, &y);
 
  printf("Before Swapping\nFirst integer = %d\nSecond integer = %d\n", x, y);
 
  t = x;
  x = y;
  y = t;
 
  printf("After Swapping\nFirst integer = %d\nSecond integer = %d\n", x, y);
 
  return 0;
}

The output of the program:
    Enter two integers
    23
    45
    Before Swapping
    First integer = 23
    Second integer = 45
    After Swapping
    First integer = 45
    Second integer = 23

#include <stdio.h>
int main()
{
   int a, b;
   
   printf("Input two integers (a & b) to swap\n");
   scanf("%d%d", &a, &b);
   
   a = a + b;
   b = a - b;
   a = a - b;
 
   printf("a = %d\nb = %d\n",a,b);
   return 0;
}

#include <stdio.h>
int main() {
   float radius, area;
 
   printf("\nEnter the radius of Circle : ");
   scanf("%d", &radius);
 
   area = 3.14 * radius * radius;
   printf("\nArea of Circle : %f", area);
 
   return (0);
}

Output : Enter the radius of Circle : 2.0
         Area of Circle : 6.14

#include <stdio.h>
int main()
{
    int i, n, sum=0;

    /* Input range to find sum of odd numbers */
    printf("Enter upper limit: ");
    scanf("%d", &n);

    /* Find the sum of all odd number */
    for(i=1; i<=n; i+=2)
    {
        sum += i;
    }

    printf("Sum of odd numbers = %d", sum);

    return 0;
}

#include <stdio.h>
int main() {
   int a[30], i, num, smallest;
 
   printf("\nEnter no of elements :");
   scanf("%d", &num);
 
   //Read n elements in an array
   for (i = 0; i < num; i++)
      scanf("%d", &a[i]);
 
   //Consider first element as smallest
   smallest = a[0];
 
   for (i = 0; i < num; i++) {
      if (a[i] < smallest) {
         smallest = a[i];
      }
   }
 
   // Print out the Result
   printf("\nSmallest Element : %d", smallest);
 
   return (0);
}

Output : 
          Enter no of elements : 5
          11 44 22 55 99
          Smallest Element : 11

#include <stdio.h>
int main()
{
    int i, n, t1 = 0, t2 = 1, nextTerm;
    printf("Enter the number of terms: ");
    scanf("%d", &n);
    printf("Fibonacci Series: ");
    for (i = 1; i <= n; ++i)
    {
        printf("%d, ", t1);
        nextTerm = t1 + t2;
        t1 = t2;
        t2 = nextTerm;
    }
    return 0;
}

Output : 
          Enter the number of terms: 10
          Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 

#include <stdio.h>
int main()
{
    int t1 = 0, t2 = 1, nextTerm = 0, n;
    printf("Enter a positive number: ");
    scanf("%d", &n);
    // displays the first two terms which is always 0 and 1
    printf("Fibonacci Series: %d, %d, ", t1, t2);
    nextTerm = t1 + t2;
    while(nextTerm <= n)
    {
        printf("%d, ",nextTerm);
        t1 = t2;
        t2 = nextTerm;
        nextTerm = t1 + t2;
    }
    
    return 0;
}

Output : 
          Enter a positive integer: 100
          Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 

#include <stdio.h>
void change(int num) {    
    printf("Before adding value inside function num=%d \n",num);    
    num=num+100;    
    printf("After adding value inside function num=%d \n", num);    
}    
int main() {    
    int x=100;    
    printf("Before function call x=%d \n", x);    
    change(x);//passing value in function    
    printf("After function call x=%d \n", x);    
return 0;  
}    

Output : 
          Before function call x=100
          Before adding value inside function num=100
          After adding value inside function num=200
          After function call x=100

#include <stdio.h>
int main()
{
    int week;

    /* Input week number from user */
    printf("Enter week number (1-7): ");
    scanf("%d", &week);


    if(week == 1)
    {
        printf("Monday");
    }
    else if(week == 2)
    {
        printf("Tuesday");
    }
    else if(week == 3)
    {
        printf("Wednesday");
    }
    else if(week == 4)
    {
        printf("Thursday");
    }
    else if(week == 5)
    {
        printf("Friday");
    }
    else if(week == 6)
    {
        printf("Saturday");
    }
    else if(week == 7)
    {
        printf("Sunday");
    }
    else
    {
        printf("Invalid Input! Please enter week number between 1-7.");
    }

    return 0;
}

#include <stdio.h>
int main()
{
    int i, j, n;

    /* Input number of rows from user */
    printf("Enter value of n: ");
    scanf("%d", &n);

    for(i=1; i<=n; i++)
    {
        /* Print i number of stars */
        for(j=1; j<=i; j++)
        {
            printf("*");
        }

        /* Move to next line */
        printf("\n");
    }

    return 0;
}

Output : Enter the value of n: 5
         *
         **
         ***
         ****
         *****

#include <stdio.h>

int main()
{
   int m, n, c, d, first[10][10], second[10][10], sum[10][10];
 
   printf("Enter the number of rows and columns of matrix\n");
   scanf("%d%d", &m, &n);
   printf("Enter the elements of first matrix\n");
 
   for (c = 0; c < m; c++)
      for (d = 0; d < n; d++)
         scanf("%d", &first[c][d]);
 
   printf("Enter the elements of second matrix\n");
 
   for (c = 0; c < m; c++)
      for (d = 0 ; d < n; d++)
         scanf("%d", &second[c][d]);
   
   printf("Sum of entered matrices:-\n");
   
   for (c = 0; c < m; c++) {
      for (d = 0 ; d < n; d++) {
         sum[c][d] = first[c][d] + second[c][d];
         printf("%d\t", sum[c][d]);
      }
      printf("\n");
   }
 
   return 0;
}

Output :

Enter the number of rows and columns of matrix
2
2
Enter the elements of first matrix
1 2
3 4
Enter the elements of second matrix
5 6 
2 1
Sum of entered matrices
6 8
5 5