Implementation Of System Calls C Program

#include<stdio.h>
#include<conio.h>
#include<dir.h>
#include<dos.h>
void main()
{
 int ch;
 clrscr();
 do
 {
 printf("\n\t\t\tMAIN MENU\n\t\t-------------------------\n");
 printf("1.To Display List of Files\n");
 printf("2.To Create New Directory\n");
 printf("3.To Change the Working Directory\n");
 printf("4.Exit\n");
 printf("Enter the Number:");
 scanf("%d",&ch);
 switch(ch)
 {
  case 1:
    list_file();
    break;

    case 2:
    directory();
    break;

  case 3:
    change_dir();
    break;

    case 4:
    exit(0);
 } }while(ch<=4);
}
int list_file()
{
 int l;
 char e[]="*.*";
 clrscr();
 printf("\t\tLIST FILE DETAIL\n\t--------------------------------------\n");
 printf("1.List All Files\n2.List of Extention Files\n3.List of Name Wise\n");
 scanf("%d",&l);
 switch(l)
 {
  case 1:
   printf("List of All(*.*) Files\n");
   subfun(e);
   break;

  case 2:
   printf("Enter the Extention:");
   scanf("%s",&e);
   subfun(e);
   break;

  case 3:
   printf("Enter the Name wise(eg:moha*.*):");
   scanf("%s",&e);
   subfun(e);
   break;
 }
 return 0;
}

int directory()
{
 struct ffblk ffblk;
 unsigned attrib;
 int d;
 char name[10],buffer[MAXPATH];
 printf("Enter the Directory name:");
 scanf("%s",&name);
 getcwd(buffer,MAXPATH);
 printf("Current directory:%s\n",buffer);

 if(_dos_getfileattr(name,&attrib)==0)
  {
     printf("%s has already available",name);
     return 0;
  }
  else
   {
    mkdir(name);
    printf("%s Directory Successfully Created\n",name);
   }
 return 0;
}

int change_dir()
{
 char buffer[MAXPATH];
 int d,d1;
 printf("\nCurrent Directory:%s\n",getcwd(buffer,MAXPATH));
 printf("\t\tChange Directory\n\t\t-----------------\n");
 printf("\n1.Step by Step Backward\n2.Goto Root Directory\n3.Forward Directory \nEnter the number:");
 scanf("%d",&d);
 switch(d)
 {
  case 1:
      chdir("..");
      break;

  case 2:
     chdir("\\");
     break;

  case 3:
     printf("Please enter the Filename:");
     scanf("%s",buffer);
     chdir(buffer);
     break;
 }

 printf("\nCurrent Directory:%s",getcwd(buffer,MAXPATH));
 return 0;
}



int subfun(s)
char s[10];
{
   struct ffblk ffblk;
   int d,p=0,i=0;
   d=findfirst(s,&ffblk,0);
   while(!d)
   {
    printf("%s\n",ffblk.ff_name);
    d=findnext(&ffblk);
    i++;
    p=p+1;
    if(p>=22)
    {
     printf("Press any key to continue:\n");
     getch();
     p=0;
    }
   }
   printf("\nTotal File:%d",i);
return 0;
}