Is there any significant difference between using if/else and switch-case in C#?

Question

What is the benefit/downside to using a switch statement vs. an if/else in C#. I can\'t imagine there being that big of a difference, other than m

Answer 1

Three reasons to prefer the switch:

• A compiler targeting native code can often compile a switch statement into one conditional branch plus an indirect jump whereas a sequence of ifs requires a sequence of conditional branches. Depending on the density of cases a great many learned papers have been written about how to compile case statements efficiently; some are linked from the lcc compiler page. (Lcc had one of the more innovative compilers for switches.)

• A switch statement is a choice among mutually exclusive alternatives and the switch syntax makes this control flow more transparent to the programmer then a nest of if-then-else statements.

• In some languages, including definitely ML and Haskell, the compiler checks to see if you have left out any cases. I view this feature as one of the major advantages of ML and Haskell. I don't know if C# can do this.

An anecdote: at a lecture he gave on receiving an award for lifetime achievement, I heard Tony Hoare say that of all the things he did in his career, there were three that he was most proud of:

• Inventing Quicksort
• Inventing the switch statement (which Tony called the case statement)
• Starting and ending his career in industry

I can't imagine living without switch.