找出一个字符串中最长重复次数的子字符串，并计算其重复次数

int find_longest_dup_str(char* src, char* dest);
int str_sub(char* src, char* sub, int pos,int len);
int str_cnt(char* src,char* sub);

/*************************************************************************
    > File Name: testmain.c
    > Author: KrisChou
    > Mail:zhoujx0219@163.com 
    > Created Time: Sun 17 Aug 2014 02:56:28 PM CST
 ************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int find_longest_dup_str(char* src, char* dest);
int str_sub(char* src, char* sub, int pos,int len);
int str_cnt(char* src,char* sub);

int main(int argc, char* argv[])
{
    char str[] = "abc fghi bc kl abcd lkm abcdefg";
    char sub[128] = "";
    int cnt;
    cnt = find_longest_dup_str(str,sub);
    printf("result: %s\ncnt: %d \n",sub,cnt);
}

int find_longest_dup_str(char* src, char* dest)
{
    int len;
    int index;
    int cnt;
    for(len = strlen(src);len > 0;len--)
    {
        for(index = 0; index + len-1 < strlen(src); index++)
        {
            str_sub(src,dest,index,len);
            if((cnt = str_cnt(src,dest)) >= 2)
            {
                return cnt;
            }
        }
    }
    return 0;
}

int str_sub(char* src, char* sub, int pos,int len)
{
    int index;
    for(index = 0; index < len;index++)
    {
        sub[index] = src[pos + index];
    }
    sub[index] = ‘\0‘;
}

int str_cnt(char* src,char* sub)
{
    int cnt = 0;
    char tmp[128];
    int index;
    int index_sub;
    for(index = 0;index + strlen(sub)-1 < strlen(src);index++)
    {
        /* method1
        for(index_sub = 0; index_sub < strlen(sub);index_sub++)
        {
            if(src[index + index_sub] != sub[index_sub])
            {
                break;
            }
        }
        if(index_sub == strlen(sub))
        {
            cnt++;
        }
        */
        /* method2
        str_sub(src,tmp,index,strlen(sub));
        if(strcmp(sub,tmp) == 0)
        {
            cnt++;
        }
        */
        // method3
        if(strncmp(src + index,sub,strlen(sub))== 0)
        {
            cnt++;
        }
    }
    return cnt;
}