#include <stdio.h>#include <unistd.h>void usage(void);/********************************************************************************NOTICE:                                                                       **This code is believed by the author to be bug free.  You are free to use and  **modify this code with the understanding that any use, either direct or        **derivative, must contain acknowledgement of its author and source.  The author**makes no warranty of any kind, expressed or implied, of merchantability or    **fitness for a particular purpose.  The author shall not be held liable for any**incidental or consequential damages in connection with or arising out of the  **furnishing, performance, or use of this software.  This software is not       **authorized for use in life support devices or systems.                        *********************************************************************************/main(int argc, char **argv){  FILE *ifp,*ofp;  int width,height,c;  extern int optind;  extern char *optarg;  if((ifp=fopen(argv[1],"r"))==NULL)   {     fprintf(stderr,"File open failed for input file %s\n",argv[1]);     usage();     exit(1);   }  optind++;  if((ofp=fopen(argv[2],"w"))==NULL)   {    fprintf(stderr,"File open failed for output file %s\n",argv[2]);    usage();    exit(2);   }  optind++;  width = 256;  height = 256;  while((c=getopt(argc,argv,"w:h:")) != EOF)  {   switch (c){    case 'h':     sscanf(optarg,"%d", &height);     break;    case 'w':     sscanf(optarg,"%d", &width);     break;             }   }  fprintf(ofp,"P5\n");  fprintf(ofp,"%d %d\n",width,height);  fprintf(ofp,"%d\n",255);  while((c=getc(ifp)) != EOF)      putc(c,ofp);}void usage(void){  fprintf(stderr,"This program converts a raw image file containing image\n");  fprintf(stderr,"values in eight bits per pixel to a a .pgm format.\n");  fprintf(stderr,"To use the program type:\n");  fprintf(stderr,"    convpgm input_file output_file [-w <width>] [-h <height>]\n");  fprintf(stderr," The default height and width are 256\n");  return;}