Ppm lab help?

[fauxdiscours]

I've got a general idea of what I need to do but my professor didnt really explain much so I'm at a loss. Can anyone take a look at the write up and my code and help me finish this? Thanks. https://goo.gl/cnPQcO

#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include <fstream>
using namespace std;
struct Pixel{
public:
	int red, green, blue;
	
	Pixel();
	
	Pixel(int red,int green,int blue);
	
	int rowCol(){
	numRows = 0, numColumns = 0;
}
	bool readPpmFile(string inputFile);

	int writePpmFile(string outputFile);

private:
	vector<vector<Pixel> > picture;

	int numRows, numColumns, maxIntensity;
};

int main(int argc, char **argv){
ifstream inputFile;
inputFile.open(argv[1]);
if(argc < 3){
cout << "usage: inputfile outputfile";
return 0;
}

return 0;
}

int rowCol(){
	
}
int writePpmFile(string outputFile){
	
}