if statement in c++ example program

  • If the conditional expression is true, the target of the if will be executed; otherwise, the target of the else, if it exists, will be executed. At no time will both be executed.
  • The conditional expression controlling the if may be any type of valid C++ expression that produces a true or false result.
  • If the Boolean expression evaluates to true, then the block of code inside the 'if' statement will be executed.

Syntax of if statement:

if (condition/boolean expression)
{
     //Block of C++ statements here
     //These statements will only execute if the condition is true
}

In this statement, if condition is true then statement are execute and if is false, then statement are not execute.

Flow Diagram

Flow Diagram of if statement

 

Example

// ifdemo.cpp 
// demonstrates IF statement 
#include using namespace std;

int main()
  { 
    int x;

    cout > x;
    if( x > 100 )
    cout << “That number is greater than 100
”; return 0;
 }

Output:

Enter a number: 2000
That number is greater than 100

Nested ifs

  • A nested if is an if statement that is the target of another if or else. Nested ifs are very common in programming.
  • The main thing to remember about nested ifs in C++ is that an else statement always refers to the nearest if statement that is within the same block as the else and not already associated with an else.

Syntax

if(i)
 {
   if(j) result = 1;
   if(k) result = 2;
 }