Parameter Passing to Functions
The parameters passed to the function are called actual parameters. For example, in the program below, 5 and 10 are actual parameters.
The parameters received by the function are called formal parameters. For example, in the above program x and y are formal parameters.
There are two most popular ways to pass parameters:
- Pass by Value: In this parameter passing method, values of actual parameters are copied to the function’s formal parameters. The actual and formal parameters are stored in different memory locations so any changes made in the functions are not reflected in the actual parameters of the caller.
- Pass by Reference: Both actual and formal parameters refer to the same locations, so any changes made inside the function are reflected in the actual parameters of the caller.
Functions in C++
A function is a set of statements that takes input, does some specific computation, and produces output. The idea is to put some commonly or repeatedly done tasks together to make a function so that instead of writing the same code again and again for different inputs, we can call this function.
In simple terms, a function is a block of code that runs only when it is called.
Syntax:
Example:
C++
// C++ Program to demonstrate working of a function #include <iostream> using namespace std; // Following function that takes two parameters 'x' and 'y' // as input and returns max of two input numbers int max( int x, int y) { if (x > y) return x; else return y; } // main function that doesn't receive any parameter and // returns integer int main() { int a = 10, b = 20; // Calling above function to find max of 'a' and 'b' int m = max(a, b); cout << "m is " << m; return 0; } |
m is 20
Time complexity: O(1)
Space complexity: O(1)