Function Call by Values and Reference

Call by Value:

• In call by value, a copy of the actual parameter's value is passed to the function.
• Changes made to the parameter within the function do not affect the original value outside the function.
• It's like giving someone a photocopy of a document; they can make changes to the copy, but the original remains untouched.
• Primitive data types like int, float, char, etc., are typically passed by value.

void swap(int a, int b) {
    int temp = a;
    a = b;
    b = temp;
}

int main() {
    int x = 5, y = 10;
    swap(x, y);
    // x and y remain unchanged after the swap function call
    return 0;
}

Call by Reference:

• In call by reference, the memory address (reference) of the actual parameter is passed to the function.
• Changes made to the parameter within the function directly affect the original value outside the function.
• It's like giving someone the original document; any changes made to it will reflect wherever it's referenced.
• Pointers are typically used to achieve call by reference in C.

void swap(int *a, int *b) {
    int temp = *a;
    *a = *b;
    *b = temp;
}

int main() {
    int x = 5, y = 10;
    swap(&x, &y);
    // x and y have been swapped
    return 0;
}