Functions and files...

This is a discussion on Functions and files... within the C++ Programming forums, part of the General Programming Boards category; Hello, I am writing a program that reads a file. If the character read is a C, it will grab ...

  1. #1
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    Functions and files...

    Hello,
    I am writing a program that reads a file. If the character read is a C, it will grab the next line which will be a radius of a circle, if the character is an R, it will obtain the next to lines which are the length and width of a reactangle, and so forth. After the program obtains the radius (for example), I need to have a fuction calculate the area of that circle based on the radius given from the file. After that, the program should send that area to a new file. How do I go about doing this? I've been trying for hours, but haven't gotten anywhere.

    Any ideas would be appreciated. Thank you.

  2. #2
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    Here is my code so far. I'm pretty stumped on how to get this working right.

    Code:
    #include <iostream>
    #include <fstream>
    #include <cmath>
    #include <iomanip>
    
    
    using namespace std;
    
    void heading();
    void printStars();
    void printLines();
    double areaCircle(ifstream& inp);
    
    
    int main()
    {
    	ifstream fin;
    	ofstream fout;
    
    	char shape;
        double radius, length, width, base, height;
    
    	fin.open("datalog.txt");
    	fout.open("myresults");
    
    	if (!fin) {
    		cout << "There was an error in opening that file." << endl;
    		cout << "Program is now shutting down..." << endl;
    		return 1;
    	}
    
    
    	while (!fin.eof()) {
    		fin >> shape;
    		switch (shape) {
    		case 'C': fin >> radius;
    			      fout >> areaCircle(inp);
                break;
    		case 'R': fin >> length;
    			      fin >> width;
    		    break;
    		case 'T': fin >> base;
    			      fin >> height;
    		}
    	}
    
    
    
        fin.close();
    	fout.close();
    
    
    	return 0;
    }
    
    void heading()
    {
    	cout << "SHAPES-R-US COMPUTING" << endl;
    	cout << endl;
    	cout << "Prepared by:" << endl;
    	cout << endl;
    	cout << "Programmer" << endl;
    	cout << endl;
    	cout << "April 1st, 2005";
    }
    
    void printStars()
    {
        int count;
    	
    	for (count = 0; count < 50; count++) {
    		cout << "*";
    	}
    }
    
    void printLines()
    {
    	int count;
    
    	for (count = 0; count < 50; count ++) {
    		cout << "-";
    	}
    }
    
    double areaCircle(ifstream& inp)
    {
    	double area;
    
    	area = 3.14 * pow(inp, 2);
    
    	return 0;
    
    
    }

  3. #3
    and the hat of wrongness Salem's Avatar
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    How about something like
    Code:
    		case 'C': fin >> radius;
    			      fout << areaCircle(radius);
    Along with
    double areaCircle(double inp);

    > return 0;
    return area;
    would be better.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  4. #4
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    I originally had that, but I keep getting error messages.

  5. #5
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    I am really stumped on this problem because all I need to do is get numbers, calculate numbers, and output the numbers into a new file with a list type format. I can't seem to output void functions in the new file, so how would I go about doing this? I can't rely on my code anymore because I am completely stuck on this and I am at the point of just switching random things around in the code until I get something.

    Any more ideas would be great.

  6. #6
    and the hat of wrongness Salem's Avatar
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    > I originally had that, but I keep getting error messages.
    Posting the code you tried, and the error messages you get would be a good idea.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  7. #7
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    I got it under control. Thanks for your help.

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