Why is 0 < -0x80000000?

Question

I have below a simple program: #include <stdio.h> #define INT32_MIN (-0x80000000) int main(void) {  long long bal = 0;    if(bal < INT32_MIN )  {   printf("Failed!!!");  }  else  {   printf("Success!!!");  }  return 0; }The condition `if(bal < INT32_MIN )` is always true. How is it possible?It works fine if I change the macro to: #define INT32_MIN (-2147483648L)Can anyone point out the issue?

Answer 1

If you are using the 8 byte long unsigned long integer, then the first 4 bytes contain F:

FF FF FF FF 80 00 00 00

which causes the underflow .

But when you define it as a long using the L suffix, those sign bits are eliminated.