目录：
- array
- '\0' 与 EOF
array:
参考：C 数组
参考：C 字符串
总结：数组对于数字型和字符型有不同，数字数组就是实际长度，而字符型数组需要增加一个 '\0'，所以对于数字数组可以这样定义 int num[] = {1, 2, 3, 4, 5}; ，而字符型数组需要预先定义长度，否则没有 '\0' 会出错，需要这样定义 char str[6] = {'h', 'e', 'l', 'l', 'o'};或者 char str[] = "hello"，会自动添加 '\0'。
#include <stdio.h>
#include <string.h>
int main(void)
{
char *r = "hello";
char s[10] = {'h','e','l','l','o'};
char ss[] = {'h','e','l','l','o'};
char t[] = "hello";
int num[] = {1, 2, 3, 4, 5};
printf ("r = %s\ns = %s\nss = %s\nt = %s\n", r, s, ss, t);
printf ("The length of r is %ld.\n", sizeof(r)); // address
printf ("The strlen of r is %ld.\n", strlen(r)); // actual length
printf ("The length of s is %ld.\n", sizeof(s)); // s[10] with '\0'
printf ("The length of ss is %ld.\n", sizeof(ss)); // print with error
printf ("The length of t is %ld.\n", sizeof(t)); // t[6] with '\0'
printf ("The strlen of t is %ld.\n", strlen(t)); // actual length
printf ("The length of num is %ld.\n", sizeof(num)/sizeof(num[0])); // actual length
for (int i = 0; i < sizeof(num)/sizeof(num[0]); i++) {
printf("%d\n", num[i]);
}
/* r = hello*/
/* s = hello*/
/* ss = hellohello ----error----*/
/* t = hello*/
/* The length of r is 8.*/
/* The strlen of r is 5.*/
/* The length of s is 10.*/
/* The length of ss is 5. ----without '\0'----*/
/* The length of t is 6.*/
/* The strlen of t is 5.*/
/* The length of num is 5.*/
/* 1*/
/* 2*/
/* 3*/
/* 4*/
/* 5*/
return 0;
}
'\0' 与 EOF 的区别
前者作为字符串的结尾标志
后者作为文件的结尾标志
如下所示：（0，与 -1）
#include <stdio.h>
#include <stdlib.h>
int main(){
printf("\'\\0\' is %d\n", '\0');
printf("EOF is %d\n", EOF);
/* '\0' is 0*/
/* EOF is -1*/
return 0;
}