`switch`¶

Case Distinctions¶

Problem: if - else if … - else

Much typing
… especially when checking for equality of integers
Direct jump table (compiler generated) would be more efficient

`if - else if` vs. `switch`¶

if (c == ' ')
    ...
else if (c == '\n' ||
         c == '\t')
    ...
else
    ...

switch (c) {
    case ' ':
        ...
        break;
    case '\n':
    case '\t':
        ...
        break;
    default:
        ...
}

`switch`¶

Labels must only be constants (and constant expressions), no variables
- known at compile time
Equality ⟶ code starting at label is executed, until the end of switch statement
break: fall through otherwise
fall through sometimes desired, but mostly not ⟶ careful!
default label is optional

When do I use it?

Finite number of values (e.g. states of a state machines)
switch over enum without default: compiler can warn about missing label ⟶ very useful!