Thread: help with small program. array issue

Code:

#include <fstream.h>
#include <stdlib.h>
// Math library
#include <math.h>

const int FileNameLen = 30, ArrayLen = 6;

// The class array
class array 
{
public: 
array(void);
//Inline functions 
inline int getsize() {return(size);}
void read(void);
void write(void);
void     draw(void);
private:

//Private - available only to member functions
int x[ArrayLen];
int size;
};


array::array(void)
{
size = 0;
}

//  Read the array

void array::read(void)
{
size = 0;
// Read each value 
do {
cout << "Enter a value\t?";
cin >> x[size++]; // Read an integer 
} while (x[size-1] != 0 && size < ArrayLen);

// Array indices run from 0 to n-1 
        size = (size == ArrayLen)? size - 2: size - 1;
}


void array::write(void)
{
//CREATE A FILE
ofstream outfile; // file object
char filename[FileNameLen]; // Store the file name
// as a character string
cout << "Enter file name ->\t";
cin >> filename;

// Open the file
outfile.open(filename);
// If you can't open the file, print an error message
// and quit
if (!outfile) {
cerr << "Cannot open " << filename << endl;
exit(1);
}


for (int i = 0;  i < size;  i++) 
outfile << "x[" << i << "] = " << x[i] << '\n';


}

void array::draw(void)
{
ifstream infile; // file object
char filename[FileNameLen]; // Store the file name
char inchar; // as a character string

cout << "Enter file name ->\t";
cin >> filename;

infile.open(filename);

if (!infile) {
cerr << "Cannot open " << filename << endl;
exit(1);
}

//Read the file  a charachter
while (!infile.eof())  
{
inchar = infile.get(); //This reads in 
//even whitespace charachters
cout << inchar; //Display it on screen

} 
infile.close();  //close the file


}



int main(void)
{ 

double sum = 0.0;
double sumOfSquares = 0.0;
double average = 0.0;
double standardDeviation = 0.0;

//display file of screen
const int FileNameLen = 30; // constant integer
ifstream infile;   //file object

average = sum / ArrayLen;
standardDeviation = sqrt(sumOfSquares / ArrayLen - average * average);


array myarray;


myarray.draw();

cout << "\nThe average is: " << average << endl;
cout << "The standard deviation is: " << standardDeviation <<endl;
return(0);
}

also consider that the program reads the following txt file that has these values
x[0] = 5
x[1] = 6
x[2] = 7
x[3] = 45

so the program has to find the average and standard deviation. can someone help me out and show me how is that done? i have the formulas and all but i dont know how to compute all that from the array.

You must create a loop to go through each element of the array. You can either do this inside a sum or average function that you add to the Array class, or you can add some sort of get method to let you get all the values in the array and make the sum function global.

Originally Posted by Salem

Is your code as badly formatted in your source code editor as it appears here?
Tidying up the presentation so that indentation follows the structure of the program would be a start.

I have actually noticed the loss of indentation when pasting code in the new version of the forum software. Of course, I noticed this when I hit Preview Post, so I fixed it. I think it may have something to do with using the Enhanced interface.