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Function Templates w/ Files

sirjames2004 (25)
Could someone please help me find the bug here? I'm trying to read a bunch of doubles into an array and print it using a template function. Ideally, I want this function to be able to print any numeric-type array. I've already tested it with integers, but for some reason it doesn't work here. Thanks in advance!

mjc_doubles.txt
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1.0
2.2
30.30
583.22
123.56
899.2313
666.56123
555.2
777.1
210.7
734.8
248.9
512.66
1116.24
1985.666
2012.1212
8.899
16.12
2323.5
2222.0022
21.7777
88.222222
99.25646
256.3
1945.1
1549.665544
27.9
28.6
2004.14
2017.17


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// File: mjcfunctemp.h
// Operating System: Linux
// Compiler: g++
// Description: Function template that will sort numeric data types

#ifndef MJCFUNCTEMP_H
#define MJCFUNCTEMP_H

#include <iostream>

// template function declarations

// outputting an array
template <typename Tp>
void mjcOutputArray(Tp arr[], const int &size)
{
	int index = 0;
	std::cout << arr[index] << std::flush;
	for(index = 1; index < size; index++)
		std::cout << ", " << arr[index] << std::flush;
	std::cout << std::endl;
}


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// File: mjctmpsrt.cpp
// Operating System: Linux
// Compiler: g++
// Description: Control file that demonstrates my number-sorting function template

// system header files
#include <iostream>
#include <fstream>
#include <cstdlib>

// programmer defined header files
#include "mjcfunctemp.h"

// global constants

const int SIZE_DARR = 20;

// control the program
int main()
{
	// define variables
	double darr[SIZE_DARR];
	int index = 0;

	std::ifstream infile;
	infile.open("mjc_doubles.txt");

	if(infile.fail())
	{
		std::cerr << "Unable to read file" << std::endl;
		exit(1);
	}
	else
	{
		index = 0;
		while(!infile.eof() || index < SIZE_DARR)
		{
			infile >> darr[index];			
			index++;
		}
	}

	infile.close();
	mjcOutputArray(darr, SIZE_DARR);
	return 0;
}
Last edited on
vlad from moscow (6539)
The problem is the invalid loop condition

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		index = 0;
		while(!infile.eof() || index < SIZE_DARR)
		{
			infile >> darr[index];			
			index++;
		}



Shall be

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		index = 0;
		while(!infile.eof() && index < SIZE_DARR)
		{
			infile >> darr[index];			
			index++;
		}



I would write the code the following way

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int main()
{
	// define variables
	double darr[SIZE_DARR] = {};

	std::ifstream infile;
	infile.open("mjc_doubles.txt");

	if(infile.fail())
	{
		std::cerr << "Unable to read file" << std::endl;
		exit(1);
	}

	int index = 0;
	while ( index < SIZE_DARR && infile >> darr[index] ) index++;


	infile.close();

	mjcOutputArray(darr, index);
	return 0;
}
Last edited on
sirjames2004 (25)
That fixed it. Thanks a lot! Figured I was missing something obvious. Until next time the fail strikes :)
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