C User Defined Functions

What Is User Defined Function

" What you have to do when I call you"
yes, the above quotes clearly define the purpose of user defined function. By speaking conceptually, a programmer can define their own sets of code inside a function and use it for n number of times using its function name.

Types

The user-defined functions are classified into four types, according to parameters and return value.

• Functions without arguments but with return values
• Functions without arguments and without return values
• Functions with arguments but without return values
• Functions with arguments and without return values

#1 Functions Without Arguments Without Return Values

The calling function will not send parameters to the called function and called function will not pass the return value to the calling function.

C program - Functions Without Arguments Without Return Values

#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
}

#2 Functions With Arguments Without Return Values

The calling function will pass parameters to the called function but called function will not pass the return value to the calling function.

C program - Functions With Arguments Without Return Values

#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
}

#3 Functions Without Arguments With Return Values

The calling function will not pass parameters to the called function but called function will pass the return value to the calling function.

C program - Functions Without Arguments With Return Values

#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
}

#4 Functions With Arguments With Return Values

The calling function will pass parameters to the called function and called function also pass the return value to the calling function.

C program - Functions With Arguments With Return Values

#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
}

Report Us

We may make mistakes(spelling, program bug, typing mistake and etc.), So we have this container to collect mistakes. We highly respect your findings.

Report

Error Line Corrected Line Send