char数组未正确初始化

Question

I have am array of chars that I'm using for bytecode. Printing them out one by one should yield the same hex values that you see here:

char toWrite[] = {'\x50','\x48','\xB8','\x00','\x00','\x00','\x00','\x00','\x00','\x00','\x00','\xFF','\xE0' };

When I try to print these values out in a loop, however, they are mangled. What I see instead is:

50 48 ffffffb8 00 00 00 00 00 00 00 ffffffff ffffffe0

Why are these chars printing wrong? I am iterating in a foreach loop, and every single element is passed to

cout << hex << (int)currentChar << endl;

Answer 1

For most systems, char is 8 bits wide and is a signed integer type. Storing \\xB8 will make its most significant bit 1, which will make it negative. And casting it to int will also result in a negative value, resulting in 0xffffffb8 if int is 32 bits wide.

You should use unsigned char :

unsigned char toWrite[] = {/*...*/};

Also, static_cast is more preferable than C-style cast:

cout << hex << static_cast<int>(currentChar) << endl;