free时偶尔出现堆不存在的bug
是这样，小弟最近用递归写了一个穷举汉明距离为n以内的全部字符串（字符只有ATCG四种）的函数，这个函数本身已经跑通了，输出也没问题，但是在释放申请的内存空间时偶尔会出现堆不存在的bug，不知是否有大佬愿意帮我看一眼，bug出现在111行的位置
程序代码：//建立群，输入一个字符串和一个距离值，输出字符串数组
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include<cstring>
#include<math.h>
//记得返回值是新的tail_count
//三种情况：正常序列、只剩一个字符、没有错误匹配
char**nbor_l(char*seq, int mis, int*amount)//依次是：序列、距离、总量的指针（为了返回总量）,需要输出两个值，序列空间和序列总量，别忘了！！
{
if(mis==0)//没有错误匹配：返回原序列
{
char **ss = (char**)malloc(4);
*amount = 1;
*ss = seq;
return ss;
//一旦传过来的seq被free掉，ss就会变成野指针，不能再调用了一定要注意啊
}
int len = strlen(seq);//字符串的长度
int loop_a = 0, loop_b = 0;
char s_c = '\0';
if (len == 1)//只剩一个字符：返回ATCG的二维数组
{
char**ss = (char**)malloc(20), **ss_ing = ss;//定义时候多留一个指针的空间以防止ss_ing变成野指针
char*s = NULL;
for (loop_a = 0; loop_a < 4; loop_a++)
{
s = (char*)malloc(2);
*(s + 1) = '\0';
switch(loop_a)
{
case 0:s_c = 'A'; break;
case 1:s_c = 'T'; break;
case 2:s_c = 'C'; break;
case 3:s_c = 'G'; break;
}
*s = s_c;
*ss_ing = s;
ss_ing++;
}
*amount = 4;
return ss;
}
else//正常序列：三步走1.分两种情况把末尾去掉调用自己2.根据字符是否相同叠合3.free上级指针，返回自己的空间
{
char*seq_n = (char*)malloc(len);
strncpy(seq_n, seq, len - 1);
*(seq_n + len - 1) = '\0';
int count_0 = 0, count_1 = 0;
char**ss_0 = nbor_l(seq_n, mis, &count_0);//0表示相同
char**ss_1 = nbor_l(seq_n, mis - 1, &count_1);//1表示不同,这两个是第一步，调用自己
int mark = 0, count = 0;
char**ss_n = (char**)malloc(4 * (3 * count_1 + count_0 + 1));
char**ss_ing = NULL, **ss_ing_n =ss_n;//这两个记得初始化
char*_tmp = NULL;
for (loop_a = 0; loop_a < 4; loop_a++)
{
switch (loop_a)
{
case 0:s_c = 'A'; break;
case 1:s_c = 'T'; break;
case 2:s_c = 'C'; break;
case 3:s_c = 'G'; break;
}
mark = (s_c == *(seq + len - 1)) ? 0 : 1;
if (mark)
{
ss_ing = ss_1;
for (loop_b = 0; loop_b < count_1; loop_b++)
{
_tmp = (char*)malloc(len + 2);
strcpy(_tmp, *ss_ing);
*(_tmp + len-1) = s_c;
*(_tmp + len) = '\0';
*ss_ing_n = _tmp;
ss_ing_n++;
ss_ing++;
count++;
}
}
else
{
ss_ing = ss_0;
for (loop_b = 0; loop_b < count_0; loop_b++)
{
_tmp = (char*)malloc(len + 2);
strcpy(_tmp, *ss_ing);
*(_tmp + len-1) = s_c;
*(_tmp + len) = '\0';
*ss_ing_n = _tmp;
ss_ing_n++;
ss_ing++;
count++;
}
}
}
*amount = count;
//free掉上个函数返回的东西防止资源浪费
ss_ing = ss_0;
/*check1//
printf("newly dropped as belows\n");
//check1*/
for (loop_a = 0; loop_a < count_0; loop_a++)
{
/*check2//
printf("%s\n", *ss_ing);
//check2*/
free((void*)(*ss_ing));
ss_ing++;
}
free((void*)ss_0);
ss_ing = ss_1;
for (loop_a = 0; loop_a < count_1; loop_a++)
{
free((void*)(*ss_ing));
ss_ing++;
}
free((void*)ss_1);
/*check3//
ss_ing = ss_n;
printf("these sequences are\n");
for (loop_a = 0; loop_a < count; loop_a++)
{
printf("%s\n", *ss_ing);
ss_ing++;
}
//check3*/
return ss_n;
}
}给大佬提前说声感谢了，此外，由于本人并非科班出身，代码的可读性、规范性和效率都比较差，因此想找个师父帮忙规范规范，有什么小任务小算法程序交给我也是完全OK的。
