title=VARIABLE cannot appear in a constant-expression

Causes

Using a variable for a switch case statement

While a switch statement often use a variable for an argument, their case statements cannot use variables as arguments.

int foo = 7;
int bar = 4;
switch(foo) {
   case bar: 
      cout << "This is case 0" << endl; 
}

Solution: Make the case statement's argument a constant

int foo = 7;
const int bar = 4;
switch(foo) {
   case bar: 
      cout << "This is case 0" << endl; 
}

Notes

• Message found in GCC version 4.5.1
• In GCC version 3.2.3, reported as: case label does not reduce to an integer constant
• This message can come up about strings- however, you cannot make a string constant