c/c++ 各类型sizeof

机器平台：X86_64 处理器

操作系统：Red Hat 4.1.2-14

编译器： gcc version 4.1.2 20070626

Size of char is:                                   1

Size of unsigned char is:                     1

Size of signed char is:                  1

Size of int is:                                    4

Size of short is:                                2

Size of long is:                                  8

Size of long int is:                             8

Size of signed int is:                           4

Size of unsigned int is:                       4

Size of unsigned long int is:                8

Size of long long int is:                       8

Size of unsigned long long is:              8

Size of float is:                    4

Size of double is:                 8

Size of long double is:          16

Size of (void *) is:           8

Size of (char *) is:           8

Size of (int *) is:             8

Size of (long *) is:           8

Size of (long long *) is:   8

Size of (float *) is:          8

Size of (double *) is:              8

——————————————————————————

机器平台： X86_32 处理器

操作系统：  Windows XP SP2

编译器：    VS2005自带的C++编译器

Size of char is:                            1

Size of unsigned char is:              1

Size of signed char is:           1

Size of int is:                       4

Size of short is:                    2

Size of long is:                     4

Size of long int is:                4

Size of signed int is:             4

Size of unsigned int is:          4

Size of unsigned long int is:         4

Size of long long int is:                8

Size of unsigned long long is:       8

Size of float is:                    4

Size of double is:                 8

Size of long double is:          8

Size of (void *) is:          4    

Size of (char *) is:          4

Size of (int *) is:             4

Size of (long *) is:          4

Size of (long long *) is:   4

Size of (float *) is:          4

Size of (double *) is:       4

其实就是所有的指针扩充为8位，long 变为8位， long doulbe 变为16位，注意double 是没有变化的

double* (*a)[3][6];
　　cout<<sizeof(a)<<endl; // 4
　　cout<<sizeof(*a)<<endl; // 72
　　cout<<sizeof(**a)<<endl; // 24
　　cout<<sizeof(***a)<<endl; // 4
　　cout<<sizeof(****a)<<endl; // 8