Switch statement in C++.

Switch statement

• The if and if-else statements permit two way branching whereas switch statement permits multiple branching. The syntax of switch statement is:

switch (var / expression)
{
   case constant1 : 
statement 1;
   break;
   case constant2 : 
statement2;
   break;
   .
   .
   default: statement3;
   break;
}

• The execution of switch statement begins with the evaluation of expression. 
• If the value of expression matches with the constant then the statements following this statement execute sequentially till it executes break. 
• The break statement transfers control to the end of the switch statement. 
• If the value of expression does not match with any constant, the statement with default is executed.

Flowchart of Switch Statement is given below.

Switch Statement

Some important points about switch statement

• The expression of switch statement must be of type integer or character type.
• The default case need not to be used at last case. It can be placed at any place.
• The case values need not to be in specific order.

For Example:

#include <iostream.h>

int main ()

{

   // local variable declaration:

   char grade = 'C';

   switch(grade)

   {

   case 'A' :

      cout << "A grade" << endl; 

      break;

   case 'B' :

      cout << "B grade" << endl;

      break;

   case 'C' :

      cout << "C grade" << endl; 

      break;

   case 'D' :

      cout << "D grade" << endl; 

      break;

   case 'F' :

      cout << "E grade" << endl; 

      break;

   default :

      cout << "Invalid grade" << endl;

   }

   cout << "Your grade is " << grade << endl;

   return 0;

}

Output :

C grade

Your grade is C

/* Source code to create a simple calculator for addition, subtraction, multiplication and division using switch...case statement in C++ programming. */

# include <iostream>

using namespace std;

int main()

{

    char o;

    float num1,num2;

    cout << "Enter operator either + or - or * or /: ";

    cin >> o;

    cout << "Enter two operands: ";

    cin >> num1 >> num2;

    switch(o) {

        case '+':

            cout << num1+num2;

            break;

        case '-':

            cout << num1-num2;

            break;

        case '*':

            cout << num1*num2;

            break;

        case '/':

            cout << num1/num2;

            break;

        default:

            /* If operator is other than +, -, * or /, error message is shown */

            cout << "Error! operator is not correct";

            break;

    }

    return 0;

}

Output

Enter operator either + or - or * or divide : -

Enter two operands:

3.4

8.4

3.4 - 8.4 = -5.0