error C2109: subscript requires array or pointer type

[yat89]

Hi everyone. I am new to C++ programming. I need to calculate the fitness for each of startNode[i] and store it into new array. I had try to do it but error appear "error C2109: subscript requires array or pointer type". I don't know how to correct this error. Hoping anyone can help me.

This is my input file in (.txt). First column refer to startNode and second coumn is objFunction.

1 153.176
2 152.146
3 155.601
4 150.824
5 126.644

Here is the code:

 
#include "stdafx.h"
#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

int main()
{
	int i;
	const int Initial_Population = 5;
	int startNode [Initial_Population];
	double objFunction [Initial_Population];

	ifstream inputFile;

	inputFile.open ("myFile.txt");

	//store data into array.
	for (i = 0; i < Initial_Population; i++)
	{
		inputFile >> startNode[i];
		inputFile >> objFunction[i];
	}

	inputFile.close();

	//declare max & min & fitness.
	double max = objFunction [0];
	double min = objFunction [0];
	double fitness;

	for (int i = 0; i < Initial_Population; i++)
	{
		//finding the maximum value z in array.
		if (objFunction[i] > max)
		{
			max = objFunction[i];
		}
		//finding the minimum value z in array.
		else if (objFunction[i] < min)
		{
			min = objFunction[i];
		}
	}

        //calculate the fitness for each startNode[i].
	for (int i = 0; i < Initial_Population; i++)
	{
		 fitness[i] = ((max - objFunction[i]) / (max - min));
	}

	cout << "fitness value: " << fitness << endl;

	system("pause");

	return 0;

}

[JLBorges]

#include <iostream>
#include <fstream>

int main()
{
    const int Initial_Population = 5;
    int startNode [Initial_Population];
    double objFunction [Initial_Population];

    //store data into array.
    {
        // open the file for input
        std::ifstream inputFile("myFile.txt");

        // we assume that the input file was opened successfully and contains valid data
        for( int i = 0; i < Initial_Population; ++i )
        inputFile >> startNode[i] >> objFunction[i];

        // the file is automagically closed when the scope is exited
    }

    double max = objFunction [0];
    double min = objFunction [0];

    for( int i = 0; i < Initial_Population; ++i )
    {
        if( objFunction[i] > max ) max = objFunction[i];
        else if( objFunction[i] < min ) min = objFunction[i];
    }

    // calculate the fitness for each startNode[i] and print it out.
    const double diff = max - min ;
    if( diff > 0 )
    {
        for( int i = 0; i < Initial_Population; ++i )
        {
            // note: fitness is not an array
            const double fitness = ( max - objFunction[i] ) / diff ;
            std::cout << "node: " << startNode[i] << "  "
                      << "fitness value: " << fitness << '\n' ;
        }
    }

    else std::cout << "max == min; infinite fitness for all\n" ;
}

[yat89]

Finally solved for calculating the fitness. Thanks for the help.