C++ If-else Statements

C++ If-else statements in c++ are the conditional statements. They are used to decide which part or code block of the program will be executed according to the pre-defined conditions true or false.  Relational operators are used to specify the conditions in c++.

cpp if statements

There are many ways to use if-else statements in C++ like if, if-else, if-else-if, and nested if. Here we discuss them one by one.


If Statement in C++

Only if statement in C++ is used to execute or skip a block of statements based on the condition is true or false.

Syntax:  if statement in C++

If (expression)
{
statement;
}

Flow chart:  if statement in C++

Example:  if statement in C++

//simple if Statement in C++
#include <iostream>  
using namespace std;  
int main()  
{  

int number = -1;

// If number is greater then 0 execute if block
  if (number > 0) {
    cout << "Your are right"<< endl;
  }

  cout << "You are out of if block";

  return 0;
} 

Output

if the number is equal to 4, it means the value is greater than 0 so the output will be

Your are right
You are out of if block

if the number is equal to -1, it means the value is less than 0 so that if condition is terminated and control goes outside the if statement. The output will be.

You are out of if block

If-else Statement in C++

If-else statement in C++ is used to execute one block of the statement when the condition is true and the other block of statements when the condition is false. In an if-else statement, both blocks of statements can never be executed and skipped at once.

Syntax:  if-else statement in C++

If (expression)
{
statements;
}
Else
{
statements;
}

Flow chart:  if statement in C++

Example: if-else statement in C++

//simple if Statement in C++
#include <iostream>  
using namespace std;  
int main()  
{  

  int number = -1;

  /* If number is greater then 0 execute if block 
  otherwise execute else part */
  if (number > 0) {
    cout << "Your are in the if part"<< endl;
  }
  else
  {
  	cout << "You are in the else part";

  }
  return 0;
} 

Output

If the number is greater than 0 execute if block otherwise execute else part

You are in the else part

If-else-if statement in C++

If-else-if statement in C++ is used to execute one block of statements from many blocks based on the true condition.

Syntax: if-else-if statement in C++

If(condition)
{
statements 1;
}
else if(condition)
{
statements 2;
}
else if(condition)
{
statements 3;
}
Else
{
statements N;
}

Flow chart: flow chart of if-else-if statement in C++

Example: if-else-if statement in c++

//if-else-if Statement in C++
#include <iostream>  
using namespace std;  
int main()  
{  

   int number1, number2;
   cout<<"Input the value of var1:"<<endl;
   cin>>number1;
   cout<<"Input the value of var2:"<<endl;
   cin>>number2;
   
    if (number1 > number2)
   {
	cout<<"number1 is greater than number2"<<endl;
   }
   else if (number2 > number1)
   {
cout<<"number2 is greater than number1"<<endl;
   }
   else
   {
	cout<<"number1 is equal to number2"<<endl;
   }
   return 0;
} 

Output 1

Input the value of var1:
8
Input the value of var2:
3
number1 is greater than number2

Output 2

Input the value of var1:
3
Input the value of var2:
8
number2 is greater than number1

Output 3

Input the value of var1:
6
Input the value of var2:
6
number1 is equal to number2

Nested if statement in C++

In the Nested if statement, the control enters the inner part only when the outer if condition is true. Users can use multiple if-else-if statements inside the if statement as required.

Syntax: Nested if statement in C++

If (condition)
{
If(condition)
{
Statements
}
Else
{
Statements
}
}
Else
{
Statements 
}

Flow chart: Nested if statement in c++

Example: Nested if statement in c++

//nested if else Statement in C++
#include <iostream>  
using namespace std;  
int main()  
{  

  int number1, number2, number3;
	 cout<<"Enter first number"<<endl;
	 cin>>number1;
	 cout<<"Enter second number"<<endl;
	 cin>>number2;
	 cout<<"Enter third number"<<endl;
	 cin>>number3;
	 if(number1>number2)
	 {
	
		  if(number1>number3)
		  {
		  cout<<"Largest: "<< number1;
		  }
		  else
		  {
		  cout<<"Largest: "<<number3;
		  }
	 }
	 else
	 {
	
		  if(number2>number3)
		  {
		   	cout<<"Largest: "<<number2;
		  }
		  else
		  {
		   	cout<<"Largest: "<<number3;
		  }
	 }
	 return 0;
} 

Output

Enter first number
5
Enter second number
8
Enter third number
3
Largest: 8

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