C Tutorial - 19 - Return from Function

What is "Return from Function" and why do we need that

"Return from Function" refers to the process of returning a value from a function to the calling code. When a function is called, it can perform some operations and then return a value to the calling code, which can then use that value for further processing.

In C and many other programming languages, a function can use the return statement to specify a value to be returned to the calling code. The syntax of the return statement is as follows:

return expression;

Here, expression is the value that the function is returning to the calling code. The type of the value returned must match the return type specified in the function declaration.

We need to use the "Return from Function" feature in C (and other programming languages) for several reasons:

1. To perform operations: Functions can perform some operations on the input parameters and return a value based on the result of those operations. For example, a function to calculate the area of a circle can take the radius as input, perform the calculation, and return the area as output.

2. To provide feedback: Functions can also provide feedback to the calling code by returning a value that indicates the success or failure of an operation. For example, a function to open a file can return a value that indicates whether the file was successfully opened or if there was an error.

3. To enable reuse: Functions can be designed to perform a specific task and return a value, which can then be used by other parts of the code. By returning a value, functions can enable code reuse and modularity, which can help to reduce code duplication and improve maintainability.

Overall, the "Return from Function" feature is an essential part of C and other programming languages, as it enables functions to perform operations, provide feedback, and enable code reuse, which are critical aspects of modern programming.

 

Return from Function Example

#include <stdio.h>

int exportFunc(int x, int y)
{
    int addition = x + y;
    return addition;
}

int simpleMultiplication()
{
    int x, y;

    printf("Value for First Num: \n");
    scanf("%d", &x);

    printf("Value for Second Num: \n");
    scanf("%d", &y);

    int multiplication = x * y;
    return multiplication;
}

int main()
{

    //printf("Result: %d \n", exportFunc(5, 10));
    //printf("Custom Result: %d \n", exportFunc(5, 10) * 2);


    printf("Multiplication: %d \n", simpleMultiplication());

    return 0;
}

Result:

Value for First Num:
10
Value for Second Num:
20
Multiplication: 200

Process returned 0 (0x0)   execution time : 3.498 s
Press any key to continue.

The above code is an example of using the "Return from Function" feature in C.

The exportFunc function takes two integer parameters, x and y, and returns the result of their addition. The function performs the addition using the + operator and stores the result in a local variable addition. The return statement is then used to return the value of addition to the calling code.

The simpleMultiplication function does not take any parameters, but instead prompts the user to enter two integers using the scanf function. The function then calculates the product of the two numbers using the * operator and stores the result in a local variable multiplication. The return statement is then used to return the value of multiplication to the calling code.

In the main function, the exportFunc and simpleMultiplication functions are called and their results are printed to the console using the printf function.

By using the "Return from Function" feature, we can perform operations, such as addition and multiplication, and return the results to the calling code for further processing or display.