Nóta
Teastaíonn údarú chun rochtain a fháil ar an leathanach seo. Is féidir leat triail a bhaint as shíniú isteach nó eolairí a athrú.
Teastaíonn údarú chun rochtain a fháil ar an leathanach seo. Is féidir leat triail a bhaint as eolairí a athrú.
'equality-operator' : signed/unsigned mismatch
Remarks
An == or != operation involved signed and unsigned variables. This could result in a loss of data.
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 example 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;
}