Return Statement in a Void Function: A Comprehensive Guide

Understanding Void Functions

Void functions in programming are known as operations that do not have a return value. When you want to execute an instruction without needing a result, you make use of a void function.

You may be wondering; but a print statement can output values, even with a void function.

#include <stdio.h>

// Void function with a printf statement
void printMessage() {
    printf("Hello, This is a void function!\n");
}

int main() {
    printf("This is the main function.\n");

    // Call the void function
    printMessage();

    printf("Back in the main function.\n");

    return 0;
}

This is the main function.
Hello, This is a void function!
Back in the main function.

To make things clear, a void function does not have a return value.

A print statement may have an output but it cannot return a value that can be used in other parts of the program.
Therefore, you can refer to void functions as Non-Value Returning functions.

The Return Statement and Why We Use It.

A return statement is used to exit a function and return a value to the calling code. The return value is optional.

#include <stdio.h>

// Define a function that returns the sum of two numbers
int add(int a, int b) {
    int sum = a + b;
    return sum; // Return the computed sum to the caller
}

int main() {
    int num1 = 1;
    int num2 = 2;

    // Call the 'add' function and store the result in 'result'
    int result = add(num1, num2);

    printf("The sum of %d and %d is %d\n", num1, num2, result);

    return 0;
}

The sum of 1 and 2 is 3

Note that the return type assigned in the function declaration must match the return type you return using the return statement in the function. For example;

Return Statements in Void Functions

You are probably confused with the sub-title; return statement in void functions.
Yes, in the previous paragraph, I only said that void functions do not have a return value. However, you can use the return keyword in a void function to terminate the execution of a void function rather than returning a value.

#include <stdio.h>

// Void function with a return statement
void exitFunction() {
    printf("I am inside a void function.\n");
    return; // This return statement will exit the function prematurely.
    printf("but I cannot be reached.\n");
}

int main() {
    printf("Hello, I inside the main function.\n");

    // Call the void function
    exitFunction();

    printf("Back into main function.\n");

    return 0;
}

Hello, I inside the main function.
I am inside a void function.
Back into main function.

Void Functions as Control Flows

A void function can also be used as a control flow to return another void function. This automatically returns the control to the caller.

#include <stdio.h>

// Void function that calls another void function
void funcB() {
    printf("Inside function B\n");
}

void funcA() {
    printf("Inside function A\n");
    funcB(); // Call another void function
    printf("Back in function A\n");
}

int main() {
    printf("Inside main\n");
    funcA();
    printf("Back in main\n");
    return 0;
}

Inside main
Inside function A
Inside function B
Back in function A
Back in main

This was a short article and I hope you learnt something new from it. Please do well to share and drop a comment. Thank you❤️