if

The if statement allows either executing or not a certain statement according to the truth-ness of a boolean, arithmetic or pointer expression. For example, the following statement will print out true because the expression between parentheses is true:

if(true)

     cout << "true\n\n";

while the statement:

if(3)

     cout << "3 is different from 0, hence interpreted as true\n\n";

prints a message on the screen, because any expression not evaluating to 0 is interpreted as true. The statement:

if(false)
    cout << "false";

will print out nothing.

Example


#include <iostream>
using namespace std;

int main()
{   
     if(3)
           cout << "3 is different from 0, hence interpreted as true\n\n";
           int i;
     cout << "Enter a number: ";
           cin >> i;
     if(i > 0)
           cout << "Number is positive\n\n";

     if(true)
         cout << "true\n\n";

     if(false)
         cout << "false";
}

Output

3 is different from 0, hence interpreted as true

Enter a number: 8
Number is positive

true

C++

if

Example

Output