i cant figure out why this error is coming up saying that "exams" are undeclared identifier. all of them?

// basic file operations

#include <iostream>
#include <fstream>
using namespace std;
void read_file_in_array(int exam[100][3]);
double calculate_total(int exam1[], int exam2[], int exam3[]); // function that calcualates grades to see how many 90,80,70,60
int main()
{
	int go,go2,go3;
	go=read_file_in_array(exam);
	go2=calculate_total(exam1,exam2,exam3);
	//go3=display_totals();
	cout << go,go2,go3;
	return 0;
}
double calculate_total(int exam1[],int exam2[],int exam3[])
{
	int calc_tot,above90=0, above80=0, above70=0, above60=0,i,j;
	calc_tot=read_file_in_array(exam);
	for(i=0;i<100;i++)
		{
			exam1[i]=exam[100][0];
			exam2[i]=exam[100][1];
			exam3[i]=exam[100][2];
			if(exam1[i] <=90 && exam1[i] >=100)
				{
					above90++;
					cout << above90;
				}
		}
		return exam3[i];
		
}
void read_file_in_array(double exam[100][3])
{
  ifstream infile;  

  int num, i=0,j=0;
  infile.open("grades.txt");// file containing numbers in 3 columns
	if(infile.fail()) // checks to see if file opended
	{
		cout << "error" << endl;
	}
  while(!infile.eof()) // reads file to end of line
	  {
		  for(i=0;i<100;i++) // array numbers less than 100
		  {
			for(j=0;j<3;j++) // while reading get 1st array or element
			infile >> exam[i][j];
			infile >> exam[i][j];
			infile >> exam[i][j];
			cout << exam[i][j] << endl;
		  }
		  exam[i][j]=exam1[i];
		  exam[i][j]=exam2[i];
		  exam[i][j]=exam3[i];
		
	  }
  infile.close();
  
}

Looking at what's posted here, your main is trying to use exam, exam1, exam2 and exam3, but you never actually declare any of them.