C Programming - Decisions Control Statement - Switch

Switch

switch statements are also used when we need our program to make a certain decision based on a condition and then execute accordingly.
Syntax :

switch (<variable>)
{
    case a-constant-expression :
        //Code to execute if <variable> == a-constant-expression
        break;

    case b-constant-expression  :
        //Code to execute if <variable> == b-constant-expression
        break;
    .
    .
    .
    case n-constant-expression :
        //Code to execute if <variable> == n-constant-expression
        break;

    default:
        //Code to execute if <variable> does not equal the value following any of the cases
}

(We will learn about break keyword in Loop section)
Example :

#include <stdio.h>

int main()
{
    int input;

    printf( "1. Play game\n" );
    printf( "2. Load game\n" );
    printf( "3. Play multi-player\n" );
    printf( "4. Exit\n" );
    printf( "Selection: " );
    scanf( "%d", &input );
    printf("\n");

    switch ( input )
    {
        case 1: //Note the colon, not a semicolon
            printf( "Play game called" );
            break;
        case 2:
            printf( "Load game called" );
            break;
        case 3:
            printf( "Play Multi-player game called" );
            break;
        case 4:
            printf( "Thanks for playing!\n" );
            break;
        default:
            printf( "Bad input, quitting!\n" );
            break;
    }
    return 0;
}

Output :
    1. Play game
    2. Load game
    3. Play multi-player
    4. Exit
    Selection: 1
    Play game called
Important points
The default case is optional.
case constant-expression can be int or char (no other datatypes are allowed).