Compiler Error C2051

Visual Studio 2015
 

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The latest version of this topic can be found at Compiler Error C2051.

case expression not constant

Case expressions must be integer constants.

The following sample generates C2051:

Copy 
// C2051.cpp  
class X {};  
  
int main() {  
   static X x;  
   int i = 0;  
  
   switch (i) {  
      case x:   // C2051 use constant expression to resolve error  
         break;  
      default:  
         break;  
   }  
}

Possible resolution:

Copy 
// C2051b.cpp  
class X {};  
  
int main() {  
   static X x;  
   int i = 0;  
  
   switch (i) {  
      case 1:  
         break;  
      default:  
         break;  
   }  
}
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