Switch Statements

[Sam Ketha]

What do switch statements do and How do you use them? I tried the w3schools page on it but didn't understand it very well.

[Wes McClintock]

switch statements are almost the same as if statements, they're just designed to be larger.
for example:

int days
    switch (days) {
      case 1: System.out.println("1day");
      case 2:  System.out.println("2 days") ;
      case 3:  System.out.println("3 days");
      case 4:  System.out.println("4 days");
      case 5: System.out.println("5 days");
      case 6: System.out.println("6 days");
      case 7:  System.out.println("7 days");
      case 8:      System.out.println("8 days");
      case 10: System.out.println("10 days")
      case 11: System.out.println("11 days");
      case 12: System.out.println("12 days");
      default: System.out.println("more than 12 days");
    }

is much faster than doing the same thing with if statements.
the "default" will be done if none of the cases return true.

[Madhan Sundararajan Devaki]

I believe, the posted code snippet should be modified as follows.

   int days = getNumberOfDays(); // Some method initializes this variable
    switch (days) {   
      case 1: System.out.println("1day");   break;
      case 2:  System.out.println("2 days") ;      break;
      case 3:  System.out.println("3 days");      break;
      case 4:  System.out.println("4 days");      break;
      case 5: System.out.println("5 days");      break;
      case 6: System.out.println("6 days");      break;
      case 7:  System.out.println("7 days");      break;
      case 8:      System.out.println("8 days");      break;
      case 10: System.out.println("10 days")      break;
      case 11: System.out.println("11 days");      break;
      case 12: System.out.println("12 days");      break;
      default: System.out.println("more than 12 days");   
    } 

NOTE: The use of break

[Jesper de Jong]

What happens if days == 9?

[Rob Spoor]

That's more than 12 days

[Campbell Ritchie]

Obviously, Jesper, switch statements use nonary arithmetic.

[Wes McClintock]

Madhan Sundararajan Devaki wrote:I believe, the posted code snippet should be modified as follows.

   int days = getNumberOfDays(); // Some method initializes this variable
    switch (days) {   
      case 1: System.out.println("1day");   break;
      case 2:  System.out.println("2 days") ;      break;
      case 3:  System.out.println("3 days");      break;
      case 4:  System.out.println("4 days");      break;
      case 5: System.out.println("5 days");      break;
      case 6: System.out.println("6 days");      break;
      case 7:  System.out.println("7 days");      break;
      case 8:      System.out.println("8 days");      break;
      case 10: System.out.println("10 days")      break;
      case 11: System.out.println("11 days");      break;
      case 12: System.out.println("12 days");      break;
      default: System.out.println("more than 12 days");   
    } 

NOTE: The use of break

yep, i did this in a hurry, sorry.

[Campbell Ritchie]

And welcome to the Ranch

[srikanth kumar aruru]

switch statements are more than if statements. switch statement is more efficient than if else statements in terms of efficiency (number of cpu cycles will be less) , code looks clean as well.

[Campbell Ritchie]

Welcome to the Ranch

The disadvantage of switch is that the values must be compile-time constants.