A function may or may not accept any argument. It may or may not return any value. Based on these facts, There are four different aspects of function calls.
- function without arguments and without return value
- function without arguments and with the return value
- function with arguments and without return value
- function with arguments and with the return value
Example of Function without argument and return value
Example 1
#include<stdio.h>
void printName();
void main ()
{
printf("Hello ");
printName();
}
void printName()
{
printf("Javatpoint");
}
Output
Hello Javatpoint
Example 2
#include<stdio.h>
void sum();
void main()
{
printf("\nGoing to calculate the sum of two numbers:");
sum();
}
void sum()
{
int a,b;
printf("\nEnter two numbers");
scanf("%d %d",&a,&b);
printf("The sum is %d",a+b);
}
Output
Going to calculate the sum of two numbers:
Enter two numbers 10
24
The sum is 34
Example for Function without argument and with return value
Example 1:
#include<stdio.h>
int sum();
void main()
{
int result;
printf("\nGoing to calculate the sum of two numbers:");
result = sum();
printf("%d",result);
}
int sum()
{
int a,b;
printf("\nEnter two numbers");
scanf("%d %d",&a,&b);
return a+b;
}
Output
Going to calculate the sum of two numbers:
Enter two numbers 10
24
The sum is 34
Example 2:
program to calculate the area of the square
#include<stdio.h>
int sum();
void main()
{
printf("Going to calculate the area of the square\n");
float area = square();
printf("The area of the square: %f\n",area);
}
int square()
{
float side;
printf("Enter the length of the side in meters: ");
scanf("%f",&side);
return side * side;
}
Output
Going to calculate the area of the square
Enter the length of the side in meters: 10
The area of the square: 100.000000
Example for Function with argument and without return value
Example 1:
#include<stdio.h>
void sum(int, int);
void main()
{
int a,b,result;
printf("\nGoing to calculate the sum of two numbers:");
printf("\nEnter two numbers:");
scanf("%d %d",&a,&b);
sum(a,b);
}
void sum(int a, int b)
{
printf("\nThe sum is %d",a+b);
}
Output
Going to calculate the sum of two numbers:
Enter two numbers 10
24
The sum is 34
Example 2:
program to calculate the average of five numbers.
#include<stdio.h>
void average(int, int, int, int, int);
void main()
{
int a,b,c,d,e;
printf("\nGoing to calculate the average of five numbers:");
printf("\nEnter five numbers:");
scanf("%d %d %d %d %d",&a,&b,&c,&d,&e);
average(a,b,c,d,e);
}
void average(int a, int b, int c, int d, int e)
{
float avg;
avg = (a+b+c+d+e)/5;
printf("The average of given five numbers : %f",avg);
}
Output
Going to calculate the average of five numbers:
Enter five numbers:10
20
30
40
50
The average of given five numbers : 30.000000
Example for Function with argument and with return value
Example 1:
#include<stdio.h>
int sum(int, int);
void main()
{
int a,b,result;
printf("\nGoing to calculate the sum of two numbers:");
printf("\nEnter two numbers:");
scanf("%d %d",&a,&b);
result = sum(a,b);
printf("\nThe sum is : %d",result);
}
int sum(int a, int b)
{
return a+b;
}
Output
Going to calculate the sum of two numbers:
Enter two numbers:10
20
The sum is : 30
Example 2:
Program to check whether a number is even or odd
#include<stdio.h>
int even_odd(int);
void main()
{
int n,flag=0;
printf("\nGoing to check whether a number is even or odd");
printf("\nEnter the number: ");
scanf("%d",&n);
flag = even_odd(n);
if(flag == 0)
{
printf("\nThe number is odd");
}
else
{
printf("\nThe number is even");
}
}
int even_odd(int n)
{
if(n%2 == 0)
{
return 1;
}
else
{
return 0;
}
}
Output
Going to check whether a number is even or odd
Enter the number: 100
The number is even
