C++ If Statement

The if statement in C++ programming language is used to execute a block of code only if a condition is true. It is used to check the truthness of the expression (In C++, all non-zero values are considered as true and zero is considered as false).

Syntax of If Statement

if(boolean_expression) {
    // code to be execute if the boolean_expression is true
}

• Condition written inside If statement parenthesis must be a boolean expression.
• The if statement first evaluates the boolean expression inside parenthesis.
• If the boolean_expression evaluated to true, then the block of code inside the if statement is executed.
• If boolean_expression evaluated to false, then the block of code inside the if statement is ignored and the next statement after if block is executed.

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C++ If statement Example Program

#include <iostream>
using namespace std;

int main(){
 
    int score;
    cout << "Enter your score : ";
    cin >> score;
    /* Using if statement to check whether 
       a student failed in examination or not*/
    if(score < 30){
     // if condition is true then print the following
        cout << "You Failed :(\n";
    }
    // This line always gets printed
 cout << "Your score : " << score;
 
    return 0;
}

Output

Enter your score : 45
Your score : 45

Enter your score : 25
You Failed :(
Your score : 25

Points to Remember about If Statement

• If statement allows the program to select an action based upon the user's input or the result of an expression. It gives us flexibility to change the logic of a program in different situations.
• The conditional_expression must be a boolean expression. It must evaluate to true or false value(In C++, all non-zero values are considered as true and zero is considered as false).
• We may use more than one condition inside if statement
  For Example:
  if(condition_one && condition_two) {
      /* if code block */
  }
• Opening and Closing Braces are optional, If the block of code of if statement contains only one statement
  For Example:
  if(condition_expression)
      statement1;
  statement2;
  In above example only statement1 will gets executed if condition_expression is true. To execute more than one statements after if statement evaluates to true, we have to use braces like the body of a function.

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C++ Operators

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C++ If Else Statement