自己使用C语言实现的库函数中的strstr函数的功能：代码如下
#include <stdio.h>static const char *strstr_t(const char *str, const char *sub_str){ const char *str_local = NULL;const char *sub_str_local = NULL;if(!str || !sub_str){ printf("fun:%s param is error\n", __FUNCTION__);return NULL;}while(*str){str_local = str;sub_str_local = sub_str;do{if(*sub_str_local == '\0'){ return str;}}while(*str_local++ == *sub_str_local++);str += 1;}return NULL;}int main(int argc, char **argv){int i = 0;char *str = NULL;char *sub_str = NULL;const char *sub = NULL;printf("input param:\n");for(i = 1; i < argc; i++){printf("argv[%d]:%s\n", i, argv[i]);}str = argv[1];sub_str = argv[2];sub = strstr_t(str, sub_str);if(sub){printf("sub string:%s\n", sub);}else{printf("error\n");}return 0;}
代码测试如下：
study$ ./strstr_T.o 12345678 567input param:argv[1]:12345678argv[2]:567sub string:5678
