Linux下对C语言数据类型存储的介绍

#include <stdio.h>#include <unistd.h>#include <fcntl.h>/*a.txt的内容 用vim "%!xxd编辑过"**//*0000000: 4201 0000 6865 6c6c 6f77 6f72 6c64 0000 B...helloworld..0000010: 0000 0000 0000 0000 0a .........*//* *分析：数值在文件中存储是以十六进制存储的，文本是以ASCII码存储的 4201 是322的存储方式, 01是高位，42是低位6865 6c6c 6f77 6f72 6c64 : helloworld的存储方式68:'h' 65:'e' 6c:'l' 6c:'l' 6f='o' 77='w' 6f='o' 72='r' 6c='l' 64='d' */struct demo {unsigned long num;char str[20];} de = {322, "helloworld"};int main(int argc, char **argv){int fd = open("a.txt", O_CREAT | O_RDWR);unsigned long num = 322;if (fd == -1) {return -1;}// write num and open with vi to see hex format ":%!xxd" .printf("szieof de is %d/n", sizeof(de));write(fd, &de, sizeof(de));return 0;}