Switch Statement

  • Till now we have Use if else statement to choose one of the many alternatives.
  • But when number of alternative increases the , complexity of the program increases and then if else statements becomes very complex.
  • To Make such problems easier C language provides a multi-way decision statement Switch statement

Switch Statement

  • Switch statement is multi-way decision statement that takes the decision from the various cases
  • A case is block of code which get's executed when certain case Expression get's matched.
  • A case expression can be repeatedly used in a switch statement.
  • Case Expression allows several alternates of action and choose one of them which will get executed during run time.
  • When you want to solve multiple option type problems, for example: Menu like program, where one value is associated with each option and you need to choose only one at a time, then, switch statement is used.
  • Switch statement is a control statement that allows us to choose only one choice among the many given choices.
  • It executes that block of code which matches the case value. If there is no match, then default block is executed(if present).

switch(expression)
{
    case value1:
        //body
        break;
       
    case value2:
        //body
        break;
        
    case value3:
        //body
        break;
    default:
        //optional case
        break;
      
}

  • You Have seen that at end of the every case we have use break statement that is because to come out from switch statement after a particular case get's matched.
  • If break statement is not used after each case , then every case gets executed after the matched case.
  • We will see what happens when we dont use break statement.
  • default case: Default case is optional case to add , that case gets executed when none of the expression get's matched.

Simple Program of switch case:
void main()
{
    int choice;

    printf("\nEnter 1 to display A");
    printf("\nEnter 2 to display B");
    printf("\nEnter 3 to display C");

    printf("\nEnter the choice: ");
    scanf("%d",&choice);

    switch(choice) //switching the choice variable.
    {
        case 1: //if choice is 1 ,
               //then this case will get execute.
            printf("%c",'A');
            break;
        case 2://if choice is 2 ,
               //then this case will get execute.
            printf("%c",'B');
            break;

        case 3://if choice is 3 ,
               //then this case will get execute.
            printf("%c",'C');
            break;

        default://if no choice is matched
               //than this case will execute.
            printf("Invalid choice");
    }
}

Output1
Enter 1 to display A
Enter 2 to display B
Enter 3 to display C

Enter the choice: 1

A
Output2
Enter 1 to display A
Enter 2 to display B
Enter 3 to display C

Enter the choice: 2

B
Output3
Enter 1 to display A
Enter 2 to display B
Enter 3 to display C

Enter the choice: 3

C

Now we will see Same program but we will remove break statement from every case:
void main()
{
    int choice;

    printf("\nEnter 1 to display A");
    printf("\nEnter 2 to display B");
    printf("\nEnter 3 to display C");

    printf("\nEnter the choice: ");
    scanf("%d",&choice);

    switch(choice) //switching the choice variable.
    {
        case 1: //if choice is 1 ,
               //then this case will get execute.
            printf("%c",'A');
            
        case 2://if choice is 2 ,
               //then this case will get execute.
            printf("%c",'B');
            

        case 3://if choice is 3 ,
               //then this case will get execute.
            printf("%c",'C');
            

        default://if no choice is matched
               //than this case will execute.
            printf("Invalid choice");
    }
}

Output1
Enter 1 to display A
Enter 2 to display B
Enter 3 to display C

Enter the choice: 1

ABC
Output2
Enter 1 to display A
Enter 2 to display B
Enter 3 to display C

Enter the choice: 2

BC
Output3
Enter 1 to display A
Enter 2 to display B
Enter 3 to display C

Enter the choice: 3

C

  • In Output1 Even if we did't choose 2 AND 3 , it displayed A , B and C,this is happen because we did not use break statements
  • As well as in Output2 even if we did not choose 3 it display B AND C
  • This is how break statement plays an important role in Switch statements
  • So , break statements are important for executing the tasks properly.


  • Switch statement are very easy and efficient to use.
  • This how switch statements works.


       Practice Programs

  • Programs Regarding If-else Statements
  • Program Regarding Nested If - statements
  • Programs Regarding loops


     Further Topics