Else statement:

An if statement can be followed by an optional else statement, which executes when the condition is false.
Syntax:

if(condition)  
{
//statements
}
else  
{
//statements
}

The compiler will test the condition:
:-If it evaluates to true, then the code inside the if statement will be executed If it evaluates to false, then the code inside the else statement will be executed.
For examle:

int mark=90;  
if(mark<33)  
{
cout<<"You failed"<<endl;  
}
else  
{
cout<<You passed"<<endl;  
}

Output:

You passed  

Note:-When only one statement is used inside the if/else, then the curly braces can be omitted.