Is an int the same as unsigned or signed?

Question

int是与unsigned或signed相同的类型吗？

Answer 1

Plain int与signed相同， signed int相同

Answer 2

C++ Standard 3.9.1/2:

There are four signed integer types : “signed char”, “short int”, “int”, and “long int.” <...>

C++ Standard 3.9.1/3:

For each of the signed integer types, there exists a corresponding ( but different ) unsigned integer type : “unsigned char”, “unsigned short int”, “unsigned int”, and “unsigned long int,” <...>

So, sizeof(int) is equal to sizeof(unsigned) . But boost::is_same< int, unsigned >::value is false.

Answer 3

ints are signed by default, as are longs .

So, int , signed and signed int are the same thing.

Similarly long and signed long are the same.

chars on the other hand, don't have a default. Implementations can consider them signed or unsigned (many have a command line switch to choose). char , signed char and unsigned char are considered three distinct types for overload resolution, template instaniation and other places.

Answer 4

int s默认签名。

Answer 5

signed int is the same as int and specifies an integer value that can have both positive and negative values.

unsigned int on the other hand can only have positive values, so the greatest positive value is much larger than that of a signed int .