C++ if Statement

Decision-making in C++ helps to write decision-driven statements and execute a particular set of code based on certain conditions.

The C++ if statement is the most simple decision-making statement. It is used to decide whether a certain statement or block of statements will be executed or not executed based on a certain type of condition.

Syntax

if(condition) 
{
// Statements to execute if
// condition is true
}

Working of if statement in C++

  1. Control falls into the if block.
  2. The flow jumps to Condition.
  3. Condition is tested.
    1. If Condition yields true, goto Step 4.
    2. If Condition yields false, goto Step 5.
  4. The if-block or the body inside the if is executed.
  5. Flow steps out of the if block.

Flowchart

If we do not provide the curly braces ‘{‘ and ‘}’ after if( condition ) then by default if statement will consider the immediate one statement to be inside its block.

For example:

if(condition)    
statement1;
statement2; // Here if the condition is true if block will consider only statement1 to be inside its block.

Examples of if statement in C++

Example 1

Below program demonstrates the use of if statement in C.

C++




// C++ program to illustrate If statement 
    
#include <iostream> 
using namespace std; 
    
int main() 
    int i = 10; 
    
    if (i < 15) { 
        cout << "10 is less than 15 \n"
    
    
    cout << "I am Not in if"
}


Output

10 is less than 15 
I am Not in if

Explanation:

  • Program starts.
  • i is initialized to 10.
  • if-condition is checked. 10 < 15, yields true.
  • “10 is less than 15” gets printed.
  • if condition yields false. “I am Not in if” is printed.

Example 2

Below program illustrates another example of if statement in C++.

C++




// C++ program to illustrate If statement
  
#include <iostream>
using namespace std;
  
int main()
{
    int i = 10;
  
    if (i > 15) {
        cout << "10 is greater than 15 \n";
    }
  
    cout << "I am Not in if";
}


Output

I am Not in if

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