Mã chấm: 268242

Main.cc: In function ‘int main()’:
Main.cc:8:35: error: ‘X’ was not declared in this scope
     scanf("%d %d %d %d", &a, &b, &X, &y);
                                   ^
Main.cc:10:12: warning: statement has no effect [-Wunused-value]
         a*x+b*y;
         ~~~^~~~