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#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
//摘自《代码之美》
//match2(regexp,text)
// 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
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] == '$' && regexp[1] == '\0') return *text == '\0';
if (*text!='\0' && (regexp[0]=='.' || regexp[0]==*text)) return matchhere(regexp+1, text+1);
return 0;
}
int match2(char *regexp, char *text) {// match: search for regexp anywhere in text
if (regexp[0] == '^') return matchhere(regexp+1, text);
do {// must look even if string is empty
if (matchhere(regexp, text)) return 1;
} while (*text++ != '\0');
return 0;
}
//match1(regexp,text)
// 字符 含义
// ? 匹配任意的单个字符
// * 匹配零个或者多个字符
int match_imp(const char *d,int dcur,const char *s,int scur) {
if(!d[dcur]) return (!s[scur])?1:0;
if (d[dcur]=='?') return match_imp(d,dcur+1,s,scur+1);
else if(d[dcur]=='*') {
do {
if (match_imp(d,dcur+1,s,scur)) return 1;
} while (s[scur++]);
return 0;
} else return (tolower(d[dcur])==tolower(s[scur]) && match_imp(d,dcur+1,s,scur+1))?1:0;
}
int match1(char* s1, char* s2) {
return match_imp(s1,0,s2,0);
}
int main() {
printf("%d==match1(abc ,abc)\n",match1("abc" ,"abc"));
printf("%d==match1(a?c ,abc)\n",match1("a?c" ,"abc"));
printf("%d==match1(a*c ,abc)\n",match1("a*c" ,"abc"));
printf("-------------------\n");
printf("%d==match1(abc ,abd)\n",match1("abc" ,"abd"));
printf("%d==match1(a?c ,abd)\n",match1("a?c" ,"abd"));
printf("%d==match1(a*c ,abd)\n",match1("a*c" ,"abd"));
printf("\n");
printf("%d==match2(abc ,abc)\n",match2("abc" ,"abc"));
printf("%d==match2(^a ,abc)\n",match2("^a" ,"abc"));
printf("%d==match2(c$ ,abc)\n",match2("c$" ,"abc"));
printf("%d==match2(a.c ,abc)\n",match2("a.c" ,"abc"));
printf("%d==match2(a.*c,abc)\n",match2("a.*c","abc"));
printf("-------------------\n");
printf("%d==match2(ABC ,abc)\n",match2("ABC" ,"abc"));
printf("%d==match2(^B ,abc)\n",match2("^B" ,"abc"));
printf("%d==match2(A$ ,abc)\n",match2("A$" ,"abc"));
printf("%d==match2(a..c,abc)\n",match2("a..c","abc"));
printf("%d==match2(a.*d,abc)\n",match2("a.*d","abc"));
return 0;
}
//1==match1(abc ,abc)
//1==match1(a?c ,abc)
//1==match1(a*c ,abc)
//-------------------
//0==match1(abc ,abd)
//0==match1(a?c ,abd)
//0==match1(a*c ,abd)
//
//1==match2(abc ,abc)
//1==match2(^a ,abc)
//1==match2(c$ ,abc)
//1==match2(a.c ,abc)
//1==match2(a.*c,abc)
//-------------------
//0==match2(ABC ,abc)
//0==match2(^B ,abc)
//0==match2(A$ ,abc)
//0==match2(a..c,abc)
//0==match2(a.*d,abc)
//