need to figure out the error in my program

#include <iostream>
#include <string>
#include <fstream>
#include <iomanip>

using namespace std;

#define Rsize 10
#define Csize 5

ifstream inputN;
ifstream inputG;
ofstream output;

//====================  READ DATA =============
void read (string stname[Rsize], int stgrades[Rsize][Csize])
{
	int r;
	int c;

	inputN.open("Names.txt");
	inputG.open("grades.txt");

	for(r= 0; r <Rsize; r++)
	{
		inputN >>stname[r];
		for(c = 0; c< Csize; c++)
			inputG >> stgrades [r][c];
	}
}
//===========================================================================
void functiontotal (int stgrades [Rsize][Csize], int sttotal [Rsize])
{	int r;
	int c;

	for (r=0; r< Rsize; r++);
	{
		for (c=0; c<Csize; c++);
			sttotal[r] = sttotal [r] + stgrades [r][c];
	}
}
//=====================================================
void average (int totalgrade [Rsize], int stavg [Rsize]
{
	int r=0;
	int csize;
	
	 for (r; r<Rsize; r++);
	 stavg[r]=totalgrade [r]/csize;
}
//====================================================
void lettergrade (int stavg [Rsize], char stlg [Rsize])
{
	int r;

	for (r=0; r<Rsize; r++)
	
	{
		if stavg [r] >=90;
		stlg [r] = 'A';
		else if stavg [r] >=80;
		stlg [r] = 'B';
		else if stavg [r] >=70;
		stlg [r] = 'c';
		else if stavg [r] >=60;
		else stlg [r] = 'f';
	}
}
//=================== DISPLAY DATA=====================
void display (string stname[Rsize], int stgrades[Rsize][Csize])
{
	int r= 0;
	int c;

	output.open("out.txt");

	for(r; r <Rsize; r++)
	{
		cout<<setw(15)<<left<<stname [r];
		for(c=0; c<Csize;c++)
			cout<<setw(5)<<right<<stgrades [r][c];
		cout<<endl;
	}
}

//================== MAIN PROGR ==================
void main()
{	  
	string  stn[Rsize];
	int stg[Rsize][Csize];
	int stt[Rsize];
	double stavg[Rsize];
	char stlg[Rsize];

    read(stn, stg);
	functiontotal(stg,stt);
	
	display(stn,stg,stt,stavg,stlg);

	inputG.close();
	inputN.close();
	output.close();

	system ("pause");
}