题目：编程实现：找出两个字符串中最大公共子字符串,如"abccade","dgcadde"的最大子串为"cad"

代码如下所示：

#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <string.h>
#include <stdlib.h>/* 编程实现：找出两个字符串中最大公共子字符串,如"abccade","dgcadde"的最大子串为"cad" *//* 采用滑动窗口的算法实现 */
bool fun(char* str1, char* str2, char* ret)
{if ((NULL == str1) || (NULL == str2) || (NULL == ret)) return false;int maxlen=0, startindex = 0, retlen = 0;int len1 = strlen(str1), len2 = strlen(str2);for (int i = 0; i < len1; i++)          //str1字符串的遍历{for (int j = 0; j < len2; j++)      //str2字符串的遍历{retlen = 0;/* 如果首字母相等，进行滑动窗口的比较 */while ((i + retlen < len1) && (j + retlen < len2) && (str1[i + retlen] == str2[j + retlen]))retlen++;if (maxlen < retlen)      //记录相同字符串最长的长度、起始索引地址。{maxlen = retlen;startindex = i;}}}if (maxlen > 0){strncpy(ret, &str1[startindex], maxlen);ret[maxlen] = '\0';}elseret[maxlen] = '\0';return true;
}int main()
{char str1[] = "abdcaddec";char str2[] = "dgcadde";char ret[10];fun(str1, str2, ret);printf("str:%s\r\n", ret);return 0;
}

运行结果如下所示：