Question

编写一个程序，判断通过键盘输入的字符串是否表示一个合法的标识符。拜托了各位 谢谢

Answer 1

#include<stdio.h> #include<string.h> int main() { char str[20]; printf("请输入字符串："); scanf("%s",str); int length; length = strlen(str); if(str[0] == '_' || (str[0] <= 'Z'&&str[0] >= 'A') || (str[0] <= 'z' &&str[0] >= 'a')) { int i; for(i = 1;i < length;i++) { if(str[i] == '_' || (str[i] <= 'Z'&&str[i] >= 'A') || (str[i] <= 'z' &&str[i] >= 'a') || (str[i] <= '9'&&str[i] >='0')) { if(i == length-1) printf("%s为合法标识符\n",str); } else { printf("%s为非法标识符\n",str); break; } } } else printf("%s为非法标识符\n",str); return 0; }