The latter is an unsigned long integer, while the former is an unsigned integer, occupying the same bytes, taking the same value range and having different suffixes at the end of the integer.

But according to different compilers, most compilers, such as vc, int and long, are the same size, all of which are 32 bits. In int, the highest bit of 1 indicates that they are all negative numbers. For example, the 32-bit int value 0xffffffff means-1, and 0xffffffe means -2.

Unsigned means unsigned, that is, all positive numbers without complement, and 0xffffffff means the 32nd power of 2, which is why the maximum value of int is 0xffffff, 3 1 power of 2, and the maximum value of unsigned is 0xffffffff, which is the 32nd power of 2.