Typeless swap

Today, one of my colleagues ask me how to create a typeless swap marco,
This is the solution.

#define MySWAP(a, b)  \
    do { \
    typeof (a) _temp = (a);\
    (a) = (b); \
    (b) = _temp; \
    } while(false)

int main()
{
        float a=1.33;
        float b=2.75;
        MySWAP(a,b);
}