Reading from a text fie into an array

abbyadnez · #1 13-Nov-2008, 14:33

I am supposed to create a program that reads 7 numbers from a text file and then out puts then it should calculate the average of the 7 numbers, find the largest number and the smallest and outputs the result into the screen and a new text file

I am having problems reading from the text file. Here is what I've come up with so far but it's not even compiling. There are errors. Can someone help me out please?

CPP / C++ / C Code:

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

void getArrayValues (int scores []);
int main (){
    int scores [7];
    getArrayValues(scores);
    return 0;
}
void getArrayValues (int scores []) {
     
     // Declare Stream and Open Text File
     ifstream inStream;
     inStream.open("biola.txt");
     
     if (inStream.fail()) {
     cerr << "Can't open file!\n";
     exit(1);
     }
 
     else {
        while (!inStream.eof()) {
        inStream >> scores[7];
           for (int j = 0; j < scores[7]; j++) {
                inStream.close();
               
     }

Thanks

ocicat · #2 13-Nov-2008, 14:47

Quote:

Originally Posted by abbyadnez

CPP / C++ / C Code:

     else {
        while (!inStream.eof()) {
        inStream >> scores[7];
           for (int j = 0; j < scores[7]; j++) {
                inStream.close();
               
     }

Given the following:

Quote:

CPP / C++ / C Code:

inStream.open("biola.txt");

...you are implying that the data is found in a text file. Therefore, the following statement:

Quote:

CPP / C++ / C Code:

inStream >> scores[7];

...will not work for a number of reasons:

You cannot read all values into the array at once.
scores[7] indicates the eighth element in the array (remember, indexing is 0-based...) which is outside the bounds of the array declared.

Because the data is text, you will need to read each line of the file as text & convert into integer values. Begin with studying the following tutorial:

http://www.cplusplus.com/doc/tutorial/files.html

...& begin by getting the string data from the file. Once you accomplished this, respond back with specific questions.

Allan · #3 27-Nov-2008, 06:57

CPP / C++ / C Code:

// it will read an integer from the text file until eof, 
int count = 0;
while( !instream.eof() )
{
  inStream >> scores[count];
  count++;
}

assume that all are integers
hope this little code will help

ocicat · #4 27-Nov-2008, 10:09

Quote:

Originally Posted by Allan

CPP / C++ / C Code:

// it will read an integer from the text file until eof, 
int count = 0;
while( !instream.eof() )
{
  inStream >> scores[count];
  count++;
}

This assumes that the number of values in the file matches the size of the array. I would suggest adding a check which will ensure that the writing past the end of the array never occurs. Likewise if too few values are specified in the file, not all array elements will be assigned values. This may or may not have dire consequences.

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Reading from a text fie into an array

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