Using a function to load an array from a text file

[brendan]

Hello, first time posting but I visit this site a lot for help and have been trying to solve this one for a while now, and I cant really find anything here or in my textbook.

Basically, my problem is that I want to load an array in main with a function called loadArray, which takes the 19 numbers from a text file. Then pass that array to my other functions. I just can't figure out the right way to call the loadArray function and have those 19 numbers be in the array initialized in main.

How do I call the loadArray function correctly? what should loadArray take as parameters and what code should it contain?

Sorry if this is a bit confusing. any suggestions or information would be greatly appreciated.

#include "stdafx.h"
#include <iostream>
#include <iomanip>
#include <stdlib.h> 
#include <fstream>
using namespace std;
int loadArray(int array[19]);
void step1(int [], int);
void step2(int [], int);
void step3(int [], int);
void step4(int [], int);
void step5(int [], int);
void step6(int [], int);
void step7(int [], int);


int main(){
	
        const int ARRAY_SIZE = 19;
	int array[ARRAY_SIZE];
	for (int count = 0; count < 20; count++){
		int array[count] = loadArray(array, count);}
	step1(array, ARRAY_SIZE);
	step2(array, ARRAY_SIZE);
	step3(array, ARRAY_SIZE);
	step4(array, ARRAY_SIZE);
	step5(array, ARRAY_SIZE);
	step6(array, ARRAY_SIZE);
	step7(array, ARRAY_SIZE);
	
	
	
	
	system("pause");
	return 0;
}
int loadArray(int array[], int count){
	ifstream inf;
	inf.open("7data.txt");
	ifstream infile("7data.txt");
	if (!infile) {
		cerr << "Input file could not be opened" << endl;
		system("pause");
		exit(1);
	}
	const int ARRAY_SIZE = 19;
	int array[ARRAY_SIZE];
	int count = 0;
	ifstream inputFile;

	infile.open("7data.txt");

	while (count < ARRAY_SIZE && inputFile >> array[count])
		count++;
	infile.close();
	return array[19];
}

void step1(int array[], const int ARRAY_SIZE){
	ofstream outfile("7output.txt");
	if (!outfile){
		cerr << "Output file could not be opened" << endl;
		exit(1);
	}
	outfile << "1. Print out the contents of the array as well as the index values from locations 0 through 19" << endl << endl;
	cout << "1. Print out the contents of the array as well as the index values from locations 0 through 19" << endl << endl;
	outfile << "Element" << setw(13) << "Value" << endl;
	cout << "Element" << setw(13) << "Value" << endl;
	
	for (int j = 0; j < 20; j++) {
		outfile << setw(7) << j << setw(13) << array[j]<< endl;
		cout << setw(7) << j << setw(13) << array[j] << endl;
	}
	
	outfile << endl << endl << endl;
	cout << endl << endl << endl;
	outfile.close();
}
void step2(int array[], const int ARRAY_SIZE){
	ofstream outfile("7output.txt");
	if (!outfile){
		cerr << "Output file could not be opened" << endl;
		exit(1);
	}
	outfile << "2. Print out the contents of the array and the index values from locations 18 to 7." << endl << endl;
	cout << "2. Print out the contents of the array and the index values from locations 18 to 7." << endl << endl;
	outfile << "Element" << setw(13) << "Value" << endl;
	cout << "Element" << setw(13) << "Value" << endl;
	
	for (int j = 18; j > 6; j--) {
		outfile << setw(7) << j << setw(13) << array[j] << endl;
		cout << setw(7) << j << setw(13) << array[j] << endl;
	}
	
	outfile << endl << endl << endl;
	cout << endl << endl << endl;
	outfile.close();
}
void step3(int array[], const int ARRAY_SIZE){
	ofstream outfile("7output.txt");
	if (!outfile){
		cerr << "Output file could not be opened" << endl;
		exit(1);
	}
	outfile << "3. Print out the contents and index values for even index values" << endl << endl;
	cout << "3. Print out the contents and index values for even index values" << endl << endl;
	outfile << "Element" << setw(13) << "Value" << endl;
	cout << "Element" << setw(13) << "Value" << endl;
	
	for (int j = 0; j < 20; j += 2) {
		outfile << setw(7) << j << setw(13) << array[j] << endl;
		cout << setw(7) << j << setw(13) << array[j] << endl;
	}
	
	outfile << endl << endl << endl;
	cout << endl << endl << endl;
	outfile.close();
}
void step4(int array[], const int ARRAY_SIZE){
	ofstream outfile("7output.txt");
	if (!outfile){
		cerr << "Output file could not be opened" << endl;
		exit(1);
	}
	outfile << "4.  Print out the even valued contents and their index values." << endl << endl;
	cout << "4. Print out the even valued contents and their index values." << endl << endl;
	outfile << "Element" << setw(13) << "Value" << endl;
	cout << "Element" << setw(13) << "Value" << endl;
	
	for (int j = 0; j < 20; j ++)
		if (array[j] % 2 == 0){
			outfile << setw(7) << j << setw(13) << array[j] << endl;
			cout << setw(7) << j << setw(13) << array[j] << endl;
		}
	
	outfile << endl << endl << endl;
	cout << endl << endl << endl;
	outfile.close();
}
void step5(int array[], const int ARRAY_SIZE){
	ofstream outfile("7output.txt");
	if (!outfile){
		cerr << "Output file could not be opened" << endl;
		exit(1);
	}
	outfile << "5. Find and print-out the largest integer stored in the array\n as well as its index location value." << endl << endl;
	cout << "5. Find and print-out the largest integer stored in the array\n as well as its index location value." << endl << endl;
	int largest = 0;
	int largenum = 0;
	for (int j = 0; j < 20; j++){
		if (array[j] > largest) {
			largest = array[j];
		}
		largenum = j;
			}
	outfile << setw(7) << largenum << setw(13) << largest << endl << endl;
	cout << setw(7) << largenum << setw(13) << largest << endl << endl;
	outfile.close();
}
void step6(int array[], const int ARRAY_SIZE){
	ofstream outfile("7output.txt");
	if (!outfile){
		cerr << "Output file could not be opened" << endl;
		exit(1);
	}
	outfile << "6. Find and print the sum and average of all integers stored in the array." << endl << endl;
	cout << "6. Find and print the sum and average of all integers stored in the array." << endl << endl;
	int totalARRAYsum = 0;
	int totalARRAYavg = 0;
	for (int j = 0; j < 20; j++){
		totalARRAYsum = totalARRAYsum + array[j];
		totalARRAYavg = totalARRAYsum / 20;


	}
	outfile << "Total Array Value: ";
	cout << "Total Array Value: ";
	outfile << setw(7) << totalARRAYsum << endl;
	cout << setw(7) << totalARRAYsum << endl;
	outfile << "Total Array Average: ";
	cout << "Total Array Average: ";
	outfile << setw(5) << totalARRAYavg << endl;
	cout << setw(5) << totalARRAYavg << endl;
	outfile << endl << endl << endl;
	cout << endl << endl << endl;
	outfile.close();
}
void step7(int array[], const int ARRAY_SIZE){
	ofstream outfile("7output.txt");
	if (!outfile){
		cerr << "Output file could not be opened" << endl;
		exit(1);
	}
	outfile << "7. Find and print-out location(s) and content values,\n if any, where the content of the array is three times its index value." << endl << endl;
	cout << "7. Find and print-out location(s) and content values,\n if any, where the content of the array is three times its index value." << endl << endl;
	for (int j = 1; j < 20; j++){
		if (j * 3 == array[j]) {
			outfile << array[j] << " is 3 times it'ss index value " << j << "\n";
			cout << array[j] << " is three times it's index value " << j << "\n";
		}
	}
	outfile.close();
}

[konstance]

A sample of what you need is this :

#include <iostream>
#include <fstream>

using namespace std;

int loadArray(int array[19],int);

int main()
{
	const int ARRAY_SIZE = 19;
	int array[ARRAY_SIZE];
	
	//fill array from file
	loadArray(array, ARRAY_SIZE);

	//print array
	for (int i = 0; i < 19; i++)
	{
		cout << array[i] << endl;
	}

	system("pause");
	return 0;
}
int loadArray(int array[], int arraySize)
{
	//open file
	ifstream infile("numbers.txt");
	if (!infile) {
		cerr << "Input file could not be opened" << endl;
		exit(1);
	}
	
	int count = 0;

	while (count < arraySize && infile >> array[count])
	{
		count++;
	}
	
	//close file
	infile.close();
}

[brendan]

Thank you. I just needed that and a global variable. I have it working now.