Thread: variable initialization error...

I am working on two different programs that use pgm pictures and make changes to each picture using histogram equilization and connected componet labeling. Now I am having 3 errors which eventhough i tried different things I can fix. Here there are:

histogram equilization
error: local variables h, w used wout been initialize(lines in bold)

Code:

#include <iostream>
#include <fstream>
#include <cmath>
#include <cstdio>

using namespace std;

void read_pgm(char * file_name)
{    int w, h;
   	char buf[80];
	FILE	 * fp;
	int cor [256][256];
	// open file for reading 
	if((fp = fopen(file_name, "r")) == NULL) {
	fprintf(stderr, "readImage: Can't open %s\n", file_name);
		exit(1);
	}

   	// Verify that the image is in PGM format. 
   	fgets(buf, 70, fp);
   	if(strncmp(buf,"P5",2) != 0){
      		fprintf(stderr, "The file %s is not in PGM format", file_name);
      		fclose(fp);
      		exit(1);
   	}

	// skip all comment lines 
   	do { fgets(buf, 70, fp); } while(buf[0] == '#');     
	sscanf(buf, "%d %d", &w, &h);
   	do { fgets(buf, 70, fp); } while(buf[0] == '#');

        // read intensity values into memory 
	//assign_mem(w, h); // assign a 2-D array cor for the image
	for (int i = 0; i < w; i++)
	  for (int j = 0; j < h; j++)
	    cor[i][j] = getc(fp);
	if (feof(fp) != 0) {
	  printf("something is wrong with this picture.\n");
	  exit(1);
	}
	fclose(fp);
}

// writes pgm grey scale image into memory cor[i][j]
void write_pgm(char * file_name)
{
	//int h,w;
	FILE	*out;
	int cor[256][256],h,w;

	if ((out = fopen(file_name, "wb")) == NULL) {
	  cout << "write_pgm: cannot open the file "<<file_name<<" for writing";
  	  //cout << file_name ;
	  //cout << " for writing";
	  //cout << endl;
          exit(1);
        }
			
	fprintf(out,"P5\n");
	fprintf(out,"%d %d\n", w, h);
	fprintf(out,"255\n");
	for (int i = 0; i < h; i++)
	  for (int j = 0; j < w; j++)
	    putc(int(cor[i][j]+0.5), out);
            // cor saves the image information

	fclose(out);
        return;
}
int main(){
	//read image
	 read_pgm("lena.pgm");
                int h,w;
	char buf[80];
	long i;
	long sum;
	long hist[256];
	long sum_hist[256];
	long Npixels = (w*h);	
	float formula = Npixels / 255;
		
	//clear histogram to 0
	 for (i=0; i < 256; i++)
		hist [i] = 0;
	 
	//calculate the histogram sum
	 for (i=0; i<Npixels; i++)
	    hist[buf[i]]++;		
	sum = 0;
	for (i = 0; i< 256; i++){
		sum += hist[i];
		sum_hist [i]= (sum * formula) + 0.5;
	}

	//transfor image using new sum 
	for (i = 0; i< Npixels; i++){
		buf[i] = (char) sum_hist[buf[i]];  
	}

	//write image
	 write_pgm("newlena.pgm");

return 0;
}

component labeling
using same read and write function as above program
error=Left of .getValue must have class/structure/union type(bold)

Code:

int main(){
	FILE *fp;
	read_pgm("lena.pgm");
	int i,j;
	int	 w, h;
	int cor[256][256];
	int pixels[256];
	int thresh;

/******************** For Connected Components Only ********************
	Applying the Component Labeling algorithm on the input image.
*/
	
	//Step 1- Fill the Intensity array backward ..That is, 255,254,253 with increasing index
	//These value will work as label for us. Maximum label range can be 255

 for ( i=0;i<256;i++) //error message name lookup of 'i' change for new ISO 'for' scope
	{	pixels[i]= 255-i;	}

/***************For Connected Components Labeling only ******************
	//Step 2- Apply the Thresholding on input image*/
	for( i=0; i<w; i++)
	{
		for(j=0; j<h; j++)
		{     if(cor[i][j] < thresh)    {
			   cor[i][j] = 255;   }
		     else     {
			   cor[i][j] = 0;     }
		}
	}
	// Now we will label the components here
	for ( i=0; i<w;i++)
	{
		for(j=0;j<h;j++)
		{      if(fp.getValue(i,j)==0)	{
			//found a component by its neighbors...	}
		}
	}
	//Step 2-Map the image data with the Intensity array
 	for ( i=0;i<w;i++)
	{    for (int j=0;j<h;j++){
			cor[i][j] = pixels[cor[i][j]]; 
		}
	}
return 0;}

>> local variables h, w used wout been initialize(lines in bold)
I'm just curious. What is your interpretation of these warnings?

gg