深入理解strstr

strstr作用展示：

#include <stdio.h>
#include <string.h>
int main()
{char str[] = "This is a simple string";char* pch;pch = strstr(str, "simple");/*strncpy(pch, "sample", 6);*/printf("%s\n",pch);return 0;
}

 结果：

模拟实现：

//模拟实现strstr
#include<stdio.h>
const char* my_strstr(const char* str1, const char* str2) {const char* cp = str1;const char* s1 = NULL;const char* s2 = NULL;while (*cp) {//cp的作用是记录可能找到匹配的字符串的起始位置s1 = cp;s2 = str2;while (*s1 == *s2 && *s1 != '\0' && *s2 != '\0') {s1++;s2++;}if (*s2 == '\0') {return cp;}cp++;}return NULL;
}
int main() {char arr1[] = "abbcdef";char arr2[] = "bbc";char*ret=my_strstr(arr1, arr2);if (ret != NULL) {printf("%s\n", ret);}elseprintf("error\n");return 0;
}