I'm doing programming which can traverse subdirectory and show lists.
If I check just file part, it was not problem. But when I do directory part,
and have to recurse program itself(I marked as "from this part"),
it show strcat segment error.
I'm thinking it's problem if string and char* recalling directory.
But I don't know exactly.
Can you guys help me? Thanks you in advance.

#include <stdio.h>
#include <getopt.h>
#include <iostream>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <string.h>
#include <fstream>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

using namespace std;

void list_dir(char* dir1_nm, char* output)  //List directory function
	DIR *pdir;  //Open directory variable
	pdir = opendir(dir1_nm);
	int icount = 0;	//Count for file number
	char* in_addr = dir1_nm; 
	struct dirent *entry;   //Directory read structure 
	struct stat statbuf;    //File inode information structure
	char* dir2_nm;   //Passing subdirectory name
	char* file_nm1;  //Making absolute path

	ofstream myout; 

	while ((entry = readdir(pdir)) != NULL)  
		stat(entry->d_name, &statbuf); //Using file name, getting link info	
		if (strcmp(entry->d_name, ".") == 0)  //If current directory, don't process
		else if (strcmp(entry->d_name, "..") == 0) //Don't process parent directory
		else if((entry->d_type) == DT_REG) //Process regular file
				strcpy(file_nm1, in_addr);
				strcat(file_nm1, "/");
				strcat(file_nm1, entry->d_name);
				cout << "file_nm1 = " << file_nm1 << endl;
			}  //end else
/* From this part */
		else if((entry->d_type) == DT_DIR)
				cout << "directory is " << entry->d_name << endl; 
				//strcpy(file_nm1, in_addr);
				//strcat(file_nm1, "/");
				//strcat(file_nm1, entry->d_name);	
				dir2_nm = entry->d_name;
				cout << "dir2_nm is " << dir2_nm << endl; 

				list_dir(dir2_nm, output);
/* Until here */
	closedir (pdir);   //Close reading input directory

int main(int argc, char * argv[])
char* dir_nm;
extern char *optarg;
extern int optind, optopt;

dir_nm = argv[2];
list_dir(dir_nm, argv[2]);  //List directory function

i Know ure new to posting here so... please read the "Before you Post" guides in the forum list. USE CODE TAGS!

You are attempting to strcat() to a variable that cannot be added to.

What address have you loaded into dir_nm ? That address space is not completely under your control (for example, how large is the space, enough to add characters to?) so you should not be changing it. You need to create you own space and load values into that space instead -- space you control.