字符串支持通配符的比较

//摘自《代码之美》
// 字符     含义
// .        匹配任意的单个字符
// ^        匹配输入字符串的开头
// $        匹配输入字符串的结尾
// *        匹配前一个字符的零个或者多个出现
#include <stdio.h>
int matchhere(char *regexp, char *text);

int matchstar(int c, char *regexp, char *text) {// matchstar: search for c*regexp at beginning of text
   do {// a * matches zero or more instances
       if (matchhere(regexp, text)) return 1;
   } while (*text != '\0' && (*text++ == c || c == '.'));
   return 0;
}
int matchhere(char *regexp, char *text) {// matchhere: search for regexp at beginning of text
   if (regexp[0] == '\0') return 1;
   if (regexp[1] == '*') return matchstar(regexp[0], regexp+2, text);
   if (regexp[0] == '$' && regexp[1] == '\0') return *text == '\0';
   if (*text!='\0' && (regexp[0]=='.' || regexp[0]==*text)) return matchhere(regexp+1, text+1);
   return 0;
}

int match(char *regexp, char *text) {// match: search for regexp anywhere in text
    if (regexp[0] == '^') return matchhere(regexp+1, text);
    do {// must look even if string is empty
        if (matchhere(regexp, text)) return 1;
    } while (*text++ != '\0');
    return 0;
}
void main() {
    printf("%d==match(abc ,abc)\n",match("abc" ,"abc"));
    printf("%d==match(^a  ,abc)\n",match("^a"  ,"abc"));
    printf("%d==match(c$  ,abc)\n",match("c$"  ,"abc"));
    printf("%d==match(a.c ,abc)\n",match("a.c" ,"abc"));
    printf("%d==match(a.*c,abc)\n",match("a.*c","abc"));
    printf("-------------------\n");
    printf("%d==match(ABC ,abc)\n",match("ABC" ,"abc"));
    printf("%d==match(^B  ,abc)\n",match("^B"  ,"abc"));
    printf("%d==match(A$  ,abc)\n",match("A$"  ,"abc"));
    printf("%d==match(a..c,abc)\n",match("a..c","abc"));
    printf("%d==match(a.*d,abc)\n",match("a.*d","abc"));
}
//1==match(abc ,abc)
//1==match(^a  ,abc)
//1==match(c$  ,abc)
//1==match(a.c ,abc)
//1==match(a.*c,abc)
//-------------------
//0==match(ABC ,abc)
//0==match(^B  ,abc)
//0==match(A$  ,abc)
//0==match(a..c,abc)
//0==match(a.*d,abc)

https://bbs.csdn.net/topics/390153970