I need to write a c program as follows Use an array to count

I need to write a c++ program as follows: Use an array to count how many pixels are zero, how many are 1, how many are 2, etc., in a PGM image. Output a histogram table of the image. Prompt the user for the name of the PGM file to histogram. You just need to figure out how to read (and make use of) the header info of the PGM, instead of reading exactly 30 values from a file. You can assume that all PGM images I give you have pixel values between 0 & 255 inclusive. Your table should have several columns of counts (so the user doesn’t need to scroll through 250+ lines of output)

I am having trouble completing this. Picture below is what I have so far.

Solution

#include <iostream>
#include <string>
#include <fstream>
#include <sstream>

using namespace std;

int main()
{
int row = 0, col = 0, num_of_rows = 0, num_of_cols = 0;
stringstream ss;
ifstream infile(\"testfile.pgm\", ios::binary);

string inputLine = \"\";

getline(infile,inputLine); // read the first line : P5
if(inputLine.compare(\"P5\") != 0) cerr << \"Version error\" << endl;
cout << \"Version : \" << inputLine << endl;

getline(infile,inputLine); // read the second line : comment
cout << \"Comment : \" << inputLine << endl;

ss << infile.rdbuf(); //read the third line : width and height
ss >> num_of_cols >> num_of_rows;
cout << num_of_cols << \" columns and \" << num_of_rows << \" rows\" << endl;

int max_val; //maximum intensity value : 255
ss >> max_val;
cout<<max_val;

unsigned char pixel;

int **pixel_value = new int*[num_of_rows];
for(int i = 0; i < num_of_rows; ++i) {
pixel_value[i] = new int[num_of_cols];
}

int **integral = new int*[num_of_rows];
for(int i = 0; i < num_of_rows; ++i) {
integral[i] = new int[num_of_cols];
}

for (row = 0; row < num_of_rows; row++){ //record the pixel values
for (col = 0; col < num_of_cols; col++){
ss >> pixel;
pixel_value[row][col]= pixel;
}
}

integral[0][0]=pixel_value[0][0];
for(int i=1; i<num_of_cols;i++){ //compute integral image
integral[0][i]=integral[0][i-1]+pixel_value[0][i];
}   
for (int i=1;i<num_of_rows; i++){
integral[i][0]=integral[i-1][0]+pixel_value[i][0];
}
for (int i = 1; i < num_of_rows; i++){
for (int j = 1; j < num_of_cols; j++){
integral[i][j] = integral[i - 1 ][j] + integral [i][j - 1] - integral[i - 1] [j - 1] + pixel_value[i][j];   
}
}

ofstream output1(\"pixel_value.txt\"); // output the intensity values of the pgm file
for (int k=0; k<num_of_rows; k++)
{
for (int r=0; r<num_of_cols; r++)
{
output1 << pixel_value[k][r] << \" \";
}
output1 << \";\" << endl;
}

ofstream output2(\"integral_value.txt\"); // output the integral image
for (int a=0; a<num_of_rows; a++)
{
for (int b=0; b<num_of_cols; b++)
{
output2 << integral[a][b] << \" \";
}
output2 << \";\" << endl;
}

for(int i = 0; i < num_of_rows; ++i) {
delete [] pixel_value[i];
}
delete [] pixel_value;

for(int i = 0; i < num_of_rows; ++i) {
delete [] integral[i];
}
delete [] integral;

infile.close();
system(\"pause\");
return 0;
}