his_exe

#include <stdio.h>
#include <stdlib.h>

int Hist_Eq(unsigned char *,unsigned char *, long , long );
int bmp_write(unsigned char *, unsigned char *,int , int , char *);
int bmp_read(unsigned char *,unsigned char *, int xsize, int , const char *);

int main() {
   unsigned char *image;
   unsigned char *newimage;
   unsigned char header[54];
   int xsize = 256;
   int ysize = 256;

   image = (unsigned char *)malloc((size_t)(xsize+2) * (ysize+2) );
   newimage = (unsigned char *)malloc((size_t)(xsize+2) * (ysize+2) );
   if (image == NULL)
     return -1;

   bmp_read(image,header, xsize, ysize, "lena");
   Hist_Eq(image,newimage,xsize,ysize);
   bmp_write(newimage,header, xsize, ysize, "NEW_lena");
   free(image);
   free(newimage);
   image = (unsigned char *)malloc((size_t)(xsize+2) * (ysize+2) );
   newimage = (unsigned char *)malloc((size_t)(xsize+2) * (ysize+2) );
   bmp_read(image,header, xsize, ysize, "HH-60");
   Hist_Eq(image,newimage,xsize,ysize);
   bmp_write(newimage,header, xsize, ysize, "NEW_HH-60");

   free(image);
   free(newimage);
 }
int Hist_Eq(unsigned char *image,unsigned char *newimage, long xsize, long ysize)
{
   int i,j;
   int x=xsize+2;
   int y=ysize+2;
   int temp=0;
   int gray[256]={0};
   double hist_array[256]={0},totalp=0;
   double hist_array_sum[256]={0};
   totalp=(double) x * (double) y;
   for(i=0;i<x*y;i++){
      gray[image[i]]++;
       }
   for(i=0;i<256;i++){

       hist_array[i]=(double)gray[i]/(double) totalp;
       }
   hist_array_sum[0]=hist_array[0];
   for(i=1;i<256;i++){
       hist_array_sum[i]=hist_array_sum[i-1]+hist_array[i];
       }

   for(i=0;i<x*y;i++){
      newimage[i]=hist_array_sum[image[i]]*255;
       }


   return 0;
}

int bmp_read(unsigned char *image,unsigned char *header, int xsize, int ysize, const char *filename) {
   char fname_bmp[128];
   FILE *fp;

   sprintf(fname_bmp, "%s.bmp", filename);

   if (!(fp = fopen(fname_bmp, "rb")))
     return -1;

   fread(header, sizeof(unsigned char), 54, fp);
   fread(image, sizeof(unsigned char), (size_t)(long)(xsize+2) * (ysize+2), fp);


   fclose(fp);
   return 0;
 }

 int bmp_write(unsigned char *image, unsigned char *header,int xsize, int ysize, char *filename) {
   /*unsigned char header[54] = {
     0x42, 0x4d, 0, 0, 0, 0, 0, 0, 0, 0,
     54, 0, 0, 0, 40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 24, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0
   };
    */
   long file_size = (long)(xsize+2) * (long)(ysize+2) + 54;
   long width, height;
   char fname_bmp[128];
   FILE *fp;

   /*header[2] = (unsigned char)(file_size &0x000000ff);
   header[3] = (file_size >> 8) & 0x000000ff;
   header[4] = (file_size >> 16) & 0x000000ff;
   header[5] = (file_size >> 24) & 0x000000ff;

   width = xsize;
   header[18] = width & 0x000000ff;
   header[19] = (width >> 8) &0x000000ff;
   header[20] = (width >> 16) &0x000000ff;
   header[21] = (width >> 24) &0x000000ff;

   height = ysize;
   header[22] = height &0x000000ff;
   header[23] = (height >> 8) &0x000000ff;
   header[24] = (height >> 16) &0x000000ff;
   header[25] = (height >> 24) &0x000000ff;
*/
   sprintf(fname_bmp, "%s.bmp", filename);

   if (!(fp = fopen(fname_bmp, "wb")))
     return -1;

   fwrite(header, sizeof(unsigned char), 54, fp);
   fwrite(image, sizeof(unsigned char), (size_t)(long)(xsize+2) * (ysize+2), fp);

   fclose(fp);
   return 0;
 }