Void Return Type

In C++, the void return type is used in functions to indicate that the function does not return any value. When a function has a void return type, it means the function does its task without producing a result that needs to be used elsewhere in the program.

For example, let's consider the function that prints values of 1D dynamic array that we used before:

main

#include <iostream>

// Function to print values of a 1D dynamic array

void printArray(const int* arr, const int size) {

for (int i = 0; i < size; ++i)

std::cout << arr[i] << " ";

std::cout << std::endl;

}

int main()

{

// Example 1D dynamic array

int size = 5;

int* dynamicArray = new int[size] { 1, 2, 3, 4, 5 };

// Call the function to print the array values

printArray(dynamicArray, size);

// Deallocate the dynamically allocated memory

delete[] dynamicArray;

}


              123456789101112131415161718192021
            
#include <iostream>

// Function to print values of a 1D dynamic array
void printArray(const int* arr, const int size) {
    for (int i = 0; i < size; ++i)
        std::cout << arr[i] << " ";
    std::cout << std::endl;
}

int main() 
{
    // Example 1D dynamic array
    int size = 5;
    int* dynamicArray = new int[size] { 1, 2, 3, 4, 5 };

    // Call the function to print the array values
    printArray(dynamicArray, size);

    // Deallocate the dynamically allocated memory
    delete[] dynamicArray;
}

We can see that the purpose of this function is to print the array, and it doesn't produce any meaningful result that must be returned. So we can use void return value in this case.

But you can still use return in a void function. For example if you want to terminate it on certain condition.

main

#include <iostream>

void displayDivision(double a, double b)

{

if (b == 0)

return;

std::cout << "displayDivision was called: " << a / b << std::endl;

}

int main()

{

// Call the function to print the division result

displayDivision(15, 8);

// Now second argument is zero

displayDivision(15, 0); // nothing happens

}


              1234567891011121314151617
            
#include <iostream>

void displayDivision(double a, double b)
{
    if (b == 0) 
        return;
    std::cout << "displayDivision was called: " << a / b << std::endl;
}

int main() 
{
    // Call the function to print the division result
    displayDivision(15, 8);
    
    // Now second argument is zero
    displayDivision(15, 0); // nothing happens
}

Alt var klart?

Takk for tilbakemeldingene dine!

Seksjon 3. Kapittel 4