Compiler Warning (level 4) C4389
'equality-operator' : signed/unsigned mismatch
An == or != operation involved signed and unsigned variables. This could result in a loss of data.
Remarks
One way to fix this warning is if you cast one of the two types when you compare signed and unsigned types.
Example
The following sample generates C4389:
// C4389.cpp
// compile with: cl /EHsc /W4 C4389.cpp
int main()
{
int a = 9;
unsigned int b = 10;
int result = 0;
if (a == b) // C4389
result = 1;
else
result = 2;
if (unsigned(a) == b) // OK
result = 3;
else
result = 4;
return result;
}