include <stdio.h>int main(){char str[4] = "abcd"
char str[4] = "abcd";定义了一个字符串数组, "abcd"里隐含了一位'\0'结束符,实际如 "abcd\0" ,字符串的长度为 5 ,而定义char str[4] 数组就少了一位啦。
应该是char str[4] = {'a','b','c','d'}吧