1	//testfile.cpp  --- test file i/o -- copyLeft by tsaiwn@csie.nctu.edu.tw
     2	#ifdef unix
     3	#ifndef __unix__
     4	#define __unix__
     5	#endif
     6	#endif
     7	#include <string.h>   /* strlen, str... */
     8	#include <stdio.h>    /** fopen, printf, ... **/
     9	#include <stdlib.h>
    10	#include <fcntl.h>    /*** O_CREAT, O_... ***/
    11	#ifdef __unix__
    12	#include <sys/stat.h> /*** S_IWRITE defined in this file ***/
    13	#else
    14	#include <sys\stat.h> /*** S_IWRITE defined in this file ***/
    15	#endif 
    16	
    17	#ifdef __unix__
    18	#include <unistd.h>   /* required for new version */
    19	#define O_TEXT O_RDWR
    20	#else
    21	#include <io.h>	      /*** open, write, read ***/
    22	#include <process.h>  /**** for "system" function calls ****/
    23	#endif
    24	
    25	#define crln printf("\n")
    26	void test1(void)
    27	 {
    28	   long kk=12345678;  /** printf --Ctrl_F1--> data type **/
    29	     printf("in test1 .. "); 
    30	     printf("\nkk=%d  ??  %ld  ???   %Ld\n",kk, kk, kk);
    31	     printf(" Correct kk=%ld\n================\n",kk);
    32	 }
    33	int main(void)
    34	{
    35	  int handle;   // an integer for System calls open/read/write/close
    36	  FILE *in, *out;   // FILE pointer for standard fxxx functions
    37	  int i,j;
    38	  char msg[] = "Hello world";
    39	    printf("\nTest file I/O --- by tsaiwn@csie.nctu.edu.tw\n");
    40	    printf("\n== call test1 to test printf with wrong %%format ==\n");
    41	    test1();
    42	    for(i=1; i <= 9; crln, i++)
    43	       for(j=1; printf("%5d",i*j), j<=8; j++);
    44	    if ((handle = open("TEST.del", O_CREAT | O_TEXT,
    45	                          S_IWRITE | S_IREAD)) == -1)
    46	    {   // handle should >= 0, if handle is -1 ==> open fail
    47	       perror("ErRor:");   return 1;
    48	    }
    49	    write(handle, "Hey, you!\n",10);   // write out 10 characters
    50	    write(handle, msg, strlen(msg));   // the length is calculated
    51	    write(handle, "\n", 1);  close(handle);
    52	    fprintf(stderr, "TEST.del created!\n");  // always on Screen
    53	#ifdef __unix__
    54	    system("/bin/ls -l  TEST.*");
    55	#else
    56	    system("dir test.*");
    57	#endif
    58	     /****** Now try C standard Library functions fopen, ...******/
    59	    if ( (in = fopen("TEST.del", "rt"))   /** Read Text **/
    60	                == NULL )    /*** NULL == 0 , see stdio.h ***/
    61	    {
    62	      fprintf(stderr, "fopen -- Cannot open input file TEST.del\n");
    63	      return 1;
    64	    }
    65	    while (!feof(in))    // Loop till feof(in)
    66	       fputc(fgetc(in), stdout);  /* fputchar(??) === putchar(??) */
    67	    fclose(in);
    68	     /****** then, type out the content of file TEST.del ******/
    69	#ifdef __unix__
    70	    printf("\n%%  cat -n TEST.del\n");
    71	    system("cat -n  TEST.del");
    72	#else
    73	    printf("\nC:> type test.del\n");
    74	    system("type TEST.del");
    75	#endif
    76	    printf("\nBye bye!\n");
    77	    return 0;
    78	}