2D array similar to excel

[gubhaus]

I am working on a project that makes a spreadsheet like excel (It is 26 by 26)
and preforms certain calculations that will do the following
Store specified data value in cells from (col1, row1) to(col2, row2).
Store random data values in cells from (col1,row1) to (col2, row2).
• Calculate minimum of data values from (col1, row1) to (col2,row2).
• Calculate maximum of data values from (col1, row1) to(col2,row2).
• Calculate sum of data values from (col1, row1)to(col2, row2).
• Calculate product of data values from (col1, row1)to (col2, row2).
• Calculate average of data values from (col1, row1)to (col2, row2).
• Calculate standard deviation of data values from (col1, row1) to (col2,row2).
• Print data values from (col1, row1)to (col2, row2).

I've done the first part but now I am at a complete loss and have no idea how to continue.

#include <cmath>
#include <cstdlib>
#include <iostream>
using namespace std;

// Global constants
const int ROWS = 26;
const int COLS = 26;
int row1;
int row2;
int col1it;
int col2it;
float data[ROWS][COLS];


//---------------------------------------------------
// Print command menu to user and get input
//---------------------------------------------------
int get_menu_choice()
{
	// Print command menu
	cout << "Welcome to MiniCalc\n"
		<< "   1) Store specified data value\n"
		<< "   2) Store random data values\n"
		<< "   3) Calculate minimum of data values\n"
		<< "   4) Calculate maximum of data values\n"
		<< "   5) Calculate sum of data values\n"
		<< "   6) Calculate product of data values\n"
		<< "   7) Calculate average of data values\n"
		<< "   8) Calculate standard deviation of data values\n"
		<< "   9) Print data values\n"
		<< "   0) Quit the program\n"
		<< "Enter command: ";

	// Get user input
	int command;
	cin >> command;
	if (command >= 0 && command <= 9)
		return command;
	else
		return get_menu_choice();
}

void specdata() {
	float data[ROWS][COLS];
	float input;
	for (int i = row1; i <= row2; i++)
	{
		for (int j = col1it; j <= col2it; j++)
		{
			cout << "What would you like to store in " << (char)(j + 65) << ":" << i << endl;
			cin >> input;
			data[i][j] = input;
		}
	}


}


void checkrange(int& row1, int& row2, int& col1it, int& col2it) {
	row1 = 0;
	row2 = 0;
	char col1 = 64;
	char col2 = 64;
	while (row1 > 26 || row1 < 1) {
		cout << "Input the First Row" << endl;
		cin >> row1;
	}
	while (col1 > 90 || col1 < 65) {
		cout << "Input the First Column" << endl;
		cin >> col1;
	}
	while (row2 > 26 || row2 < 1) {
		cout << "Input the Second Row" << endl;
		cin >> row2;
	}
	while (col2 > 90 || col2 < 65) {
		cout << "Input the Second Column" << endl;
		cin >> col2;
	}
	col1it = col1 - 65;
	col2it = col2 -65;

}
//---------------------------------------------------
// Main program
//---------------------------------------------------
int main()
{
	// Declare spreadsheet
	

	// Loop processing menu commands
	int command = get_menu_choice();
	while (command != 0)
	{
		if (command == 1) {
			checkrange(row1, row2, col1it, col2it);
			specdata();

		}
		else if (command == 2) {
			checkrange(row1, row2, col1it, col2it);

		}
		else if (command == 3) {
			checkrange(row1, row2, col1it, col2it);
		}
		else if (command == 4) {
			checkrange(row1, row2, col1it, col2it);
		}
		else if (command == 5) {
			checkrange(row1, row2, col1it, col2it);
		}
		else if (command == 6) {
			checkrange(row1, row2, col1it, col2it);
		}
		else if (command == 7){
			checkrange(row1, row2, col1it, col2it);
		}
		else if (command == 8) {
			checkrange(row1, row2, col1it, col2it);
		}
		else if (command == 9) {
			checkrange(row1, row2, col1it, col2it);
		}
		command = get_menu_choice();
	}
	return 0;
}