C语言实现文件命名按顺序递增

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<dirent.h>
const char NUM[] = {'0','1','2','3','4','5','6','7','8','9'};
int get_10(int num)
{
int i, out = 1;
if(!num)return 1;
else
{
for(i = 1; i <= num; i++)
out *= 10;
return out;
}
}
int num_over(int *num_str, int len)
{
int i, out = 0;
for(i = 0; i < len; i++)
{
out += num_str[i] * get_10(len - i -1);
}
return out;
}
int get_num(char *str)
{
int i, j, k = 0, len;
int num[10];
len = strlen(str);
for(i = 0; i < len; i++)
{
for(j = 0; j < strlen(NUM); j++)
{
if(NUM[j] == str[i])
{
num[k++] = j;
break;
}
}
}
return(num_over(num, k));
}
void change_str(char *str, char *a, char *b)
{
char *p, q[100] = {0};
p = strstr(str, a);
p += strlen(a);
strcpy(q, p);
*(p - strlen(a)) = 0;
strcat(str, b);
strcat(str, q);
}
int main()
{
const char dir[512] = "D:\\work\\工作\\延庆\\已完成\\已交付\\北京市_延庆_格兰山小区\\北京市_延庆_格兰山小区1号楼\\";
const char str[512] = "1号楼";
char filename[512] = {0}, a[10], b[10], *p, name_temp[512] = {0};
char new_name[512] = {0}, old_name [512] = {0};
char tmp[512] = "COPY ";
char name_tmp[512] = {0}, str_tmp[512] = {0};
int i, j;
DIR *directory_pointer;
strcpy(old_name, dir);
strcpy(new_name, dir);
struct dirent *entry;
if((directory_pointer=opendir(dir))==NULL)
printf( "Error opening \n ");
else
{
while((entry=readdir(directory_pointer))!=NULL)
{
if(p = strstr(entry-> d_name, str ))
{
strcpy(filename, entry-> d_name);
break;
}
}
sprintf(a, "%d", get_num(str));
printf("获取起始数：%d\n输入终止数：\n", get_num(str));
scanf("%d",&j);
for(i = get_num(str) + 1; i <= j; i++)
{
sprintf(b, "%d" , i);
strcpy(str_tmp, str);
change_str(str_tmp, a, b);
strcpy(name_temp, filename);
strcat(old_name, name_temp);
change_str(name_temp, str, str_tmp);
strcat(new_name, name_temp);
strcat(tmp, old_name);
strcat(tmp, " ");
strcat(tmp, new_name);
printf("%s\n", name_temp);
system(tmp);
strcpy(tmp, "COPY ");
strcpy(b, "\0");
strcpy(str_tmp, "\0");
strcpy(old_name, dir);
strcpy(new_name, dir);
}
closedir(directory_pointer);
}
}