C1809: Integer value for switch-expression expected

[ERROR]

The specified switch expression evaluated to an illegal type.

  float f;

  

  void main(void) {

  

    switch(f) {

  

    case 1:

  

      f=2.1f;

  

      break;

  

    case 2:

  

      f=2.1f;

  

      break;

  

    }

  

  }

  

A switch expression must evaluate to an integral type, or a class type that has an unambiguous conversion to an integral type.