Function Definition

Pass by value is used where the value of x is not modified using the function fun().

C++

// C++ Program to demonstrate function definition
#include <iostream>
using namespace std;
 
void fun(int x)
{
    // definition of
    // function
    x = 30;
}
 
int main()
{
    int x = 20;
    fun(x);
    cout << "x = " << x;
    return 0;
}

Output

x = 20

Time complexity: O(1)

Space complexity: O(1)

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:

Syntax of Function

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;
}

Output

m is 20

Time complexity: O(1)

Space complexity: O(1)

Function Definition

C++

Functions in C++

C++

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