《C和指针》6.18.1匹配字符

#include <stdio.h>char *find_char(char const*source, char const *chars){char *p_chars;if (source == NULL || chars == NULL || source == "" || chars == "")return NULL;for (; *source != '\0'; source++){for (p_chars = (char *)chars; *p_chars != '\0'; p_chars++){if (*p_chars == *source)return (char *)source;}}return NULL;}int main(){char *source = "ABCDEF";char *chars = "XRCQEF";char *ret_char = find_char(source, chars);printf("%c\n",*ret_char);return 0;}