void swap(int *first,int *second){
    int temp = *first;
    *first = *second;
    *second = temp;
}


int a=3,b=2;
swap(&a,&b);

#define swap(a,b){   \
    int _temp = (a); \
    (a) = _b;        \
    (b) = _temp;     \
}