在c运行库头文件<stdint.h>中typedef各种类型的int
typedef signed char int8_t;
typedef unsigned char uint8_t;
typedef signed int int16_t;
typedef unsigned int uint16_t;
typedef signed long int int32_t;
typedef unsigned long int uint32_t;
typedef signed long long int int64_t;
typedef unsigned long long int uint64_t;