Programming Forums - read integers from file into an array

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read integers from file into an array

having a problem with a program not sure what I'm doing wrong. I to write this program that
inputs integer data from a file into an array of size 100. We have to create a
variable to keep track of how many numbers were read into the array, then
determine where in the array the highest and lowest value reside.

here's what I have so far...

#include <iostream>
#include <fstream>
#include <string>
 
 
using namespace std;
 
int main()
{
    int i, max, min, maxNumber, minNumber;
    string myArray;
    max = 0;
    min = 0;
 
    ifstream inFile;
    ofstream outFile;
 
    inFile.open ("inputNums.txt");
    outFile.open ("finalResults.txt");
 
    inFile >> myArray;
 
    for (i = 0; i <= 100; i++)
         {   inFile >> myArray[i];
 
 
    outFile << "The maximum value is " << max << " found at array index position" << endl;
    outFile << endl;
 
    outFile << "The minimun value is " << min << "found at array index position" << endl;
    outFile << endl;
 
    outFile << "There are  " << endl;
    outFile << endl;
 
    outFile << "Thank You!" << endl;
 
    inFile.close();
    outFile.close();
}   
 
 
 system ("pause");
 return 0;
}

Re: read integers from file into an array

line 11:
myArray is not an int array. It needs to be declared like this:

int myArray[100] = {0};

line 23: do not make the assumption that the file contains 100 integers -- maybe it only contains 10, maybe it contains a million. The idea is to read the file until end-of-file is reached or your array is filled up, whichever somes forst. So the way to code that loop is like this:

while( inFile >> myArray[i]) 

    ++i;

max. To find the max value, just keep track of the maximum value as they are being read from the file

int max = -1000;

int i = 0;

while( inFile >> myArray[i]) 

{

    if( myArray[i] > max)

         max = myArray[i];

    ++i;

}

Re: read integers from file into an array

what about the min value? do i use the else if statement?

Re: read integers from file into an array

, max = min;

        for(i = 1; i < size; ++i)

        {

                if (nums[i] < min)

                        min = nums[i];

                else if (nums[i] > max)

                        max = nums[i];

        }

can I do it like this?

Re: read integers from file into an array

>>do i use the else if statement
No, just use another variable and statement like I did for the max value. I wouldn't use the else statement because maybe the current value just read affects both min and max.

int max = 0;

int min = 0;

int i = 0;

while( inFile >> myArray[i]) 

{

     if( i == 0) // first time throug

    {

         max = min = myArray[i];

    }

    if( myArray[i] > max)

         max = myArray[i];

    if( myArray[i] < min)

         min = myArray[i];

    ++i;

}

And you forgot to add code tags

Re: read integers from file into an array

I'm sorry about the code tags...I'm a newbie, still learning

Re: read integers from file into an array

I'm sorry.....I am so lost....do I need lines 10-13? and where would I place the

int max = [-1000];

int i = [0];

while( inFile >> myArray[i]) 

{

    if( myArray[i] > max)

         max = myArray[i];

    ++i;

}

also what is the code tags?

Re: read integers from file into an array

>>do I need lines 10-13?
yes. But you need to change line 11 as I said previously.

>>where would I place this
replace lines 23 and 24 with the lines that were in my most post #5

>>also what is the code tags?
Read your PM that I sent you. It shows you how to do it.

Re: read integers from file into an array

I treid using your post #2 about line 11 and I keep getting a error saying invalid initializer...