编程实现LINUX下目录的层层遍历

/*************************************************************************
  > File Name: treedir.c
  > Author: KrisChou
  > Mail:zhoujx0219@163.com 
  > Created Time: Tue 19 Aug 2014 05:04:50 PM CST
 ************************************************************************/

#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>

void print_tree(char* dirname, int spc_cnt);

int main(int argc, char* argv[])// ./main dir
{
    if(argc == 1)
    {
        print_tree(".", 0);
    }else if(argc == 2)
    {
        print_tree(argv[1], 0);
    }
    return 0 ;
}

void print_tree(char* dirname, int spc_cnt)
{
    DIR* pdir ;                       //目录指针
    struct dirent* pent ;             //可以获取目录下子项d_name的结构体指针
    struct stat my_stat ;             //根据绝对路径，获取文件信息的结构体           
    
    char old_path[128]="";            //保存原来的工作路径         
    getcwd(old_path, 128);            
    
    pdir = opendir(dirname);          //打开目录
    if(pdir == NULL)
    {
        perror("opendir");
        exit(1);
    }
    
    chdir(dirname);                   //切换到需要遍历的目录
    
    while((pent = readdir(pdir)) != NULL)
    {
        if(strncmp(pent ->d_name, ".", 1) == 0 || strncmp(pent->d_name,"..", 2) == 0)
        {
            continue ;
        }
        
        memset(&my_stat, 0 , sizeof(my_stat));
        if(stat(pent ->d_name, &my_stat) == -1)
        {
            perror("stat");
            exit(1);
        }
        
        if(S_ISDIR(my_stat.st_mode))
        {
            printf("%*s%s\n",spc_cnt," ",pent ->d_name);
            print_tree(pent ->d_name, spc_cnt + 5);
        }else 
        {
            printf("%*s%s\n",spc_cnt," ",pent ->d_name);
        }
    }
    
    closedir(pdir);
    chdir(old_path); //程序结束切换回原来的目录
}