C++ LANGUAGE IF ELSE IF ELSE STATEMENT PAGE 60

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C++ LANGUAGE IF ELSE IF ELSE STATEMENT

if...else if...else Statement 


An if statement can be followed by an optional else if...else statement, 
which is very usefull to test various conditions using single if...else if statement. 
When using if , else if , else statements there are few points to keep in mind. 

• An if can have zero or one else's and it must come after any else if's. 



• An if can have zero to many else if's and they must come before the else. 

• Once an else if succeeds, none of he remaining else if's or else's will be tested. 

Syntax 
The syntax of an if...else if...else statement in C++ is: 
if(boolean_expression 1) 
{ 
   // Executes when the boolean expression 1 is true 
} 
else if( boolean_expression 2) 
{ 
   // Executes when the boolean expression 2 is true 
} 
else if( boolean_expression 3) 
{ 
   // Executes when the boolean expression 3 is true 
} 
else  
{ 
   // executes when the none of the above condition is true. 
} 
Example 
#include <iostream> 
using namespace std; 
  
int main () 
{ 
   // local variable declaration: 
   int a = 100; 
  
   // check the boolean condition 
   if( a == 10 ) 
   { 
       // if condition is true then print the following 
       cout << "Value of a is 10" << endl; 
   } 
   else if( a == 20 ) 
   { 
       // if else if condition is true 
       cout << "Value of a is 20" << endl; 
   } 
   else if( a == 30 ) 
   { 
       // if else if condition is true  
       cout << "Value of a is 30" << endl; 
   } 
   else 
   { 
       // if none of the conditions is true 
       cout << "Value of a is not matching" << endl; 
   } 
   cout << "Exact value of a is : " << a << endl; 
  
   return 0; 
} 
When the above code is compiled and executed, it produces the following result: 
Value of a is not matching 
Exact value of a is : 100