NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/lang/c++-part2/12049

Text File | 1996-08-05 | 4.9 KB | 236 lines

Path: newsfeed.internetmci.com!panix!not-for-mail
From: [e-mail] (Arthur Cinader Jr)
Newsgroups: comp.lang.c++,gnu.help.g++
Subject: Out of Memory error?
Date: 17 Mar 1996 20:06:17 -0500
Organization: Panix
Message-ID: <4iicu9$[e-mail]>
NNTP-Posting-Host: panix.com

I must be making progress in my effort to learn to program,
because this is a new error for me!

My program uses a class Args which has two dynamically
allocated arrays of strings one for labels and the other for values.

An Args object is created by a static function in the Triangle
class and passed to main.  The values are loaded into the
Args object in main and the object is then passed back to a
"make instance of" static function in Triangle. However, when
I try to load the third value, I get:

assertion "val[valcnt] != 0" failed: file "args.C", line 49
zsh: abort (core dumped)  ./a.out

A new one on me.  I have run through the program, I know that
it is crude, but I think that it should be working.  The
failed assert indicates to me that I have run out of
memory...how can this be.  What do I do now!?!  Below is the
code...any pointers in how to think about this type of issue/problem
will be appreciated!

Arthur

************
// shape.h
// declaration of abstract base class shape
#ifndef SHAPE_H
#define SHAPE_H

class Shape {
public:
        virtual void draw() const = 0; // pure virtual
};

#endif

// point.h
// Declaration for class Point which extends Shape

#ifndef POINT_H
#define POINT_H

#include "shape.h"

class Point : public Shape {
public:
        Point(float = 0.0, float = 0.0);
        float getx() const;
        float gety() const;
        void setfill(char);
        virtual void draw() const;

private:
        float x;
        float y;
        char fill;
};

#endif

// point.C
// definitions for abstract base class

#include <iostream.h> // included for draw function to be
                                          // replaced with
curses routine
#include "point.h"

// Constructor
Point::Point(float a, float b)
{
        x = a;
        y = b;
        setfill('*');
}

// Get x
float Point::getx() const { return x; }

// Get y
float Point::gety() const { return y; }

// Set fill
void Point::setfill(char c) { fill = c; }

// Draw
void Point::draw() const
{
        cout << "[" << x << ", " << y << "]" << endl;
}

// triangle.h
// declaration of class Triangle extends shape

#ifndef TRIANGLE_H
#define TRIANGLE_H

#include "point.h"
#include "args.h"

class Triangle : public Point {
public:
        Triangle(float = 0.0, float = 0.0, float = 0.0);
        float gets() const;
        virtual void draw() const;

        static Args &getargs();
        static Triangle *makeinstance(Args &);
private:
        float side;
};

#endif

// triangle.C
// Class definition

#include <iostream.h>
#include <string.h>
#include <assert.h>
#include <stdlib.h>
#include "tri.h"
#include "args.h"

// Static Functions

// Get Args
Args &Triangle::getargs()
{
        Args &a = *(new Args());
        a.addlbl("X coordinate: ");
        a.addlbl("Y coordinate: ");
        a.addlbl("Length of sides: ");
        a.addlbl("Fill character: ");

        return a;
}

// Make instance of triangle
Triangle *Triangle::makeinstance(Args &a)
{
        const int MINX = 0;
        const int MINY = 0;
        const int MAXX = 80;
        const int MAXY = 15;
        float tmpx;
        float tmpy;
        float tmps;
        char tmpfill;

        // Pop x value
        a.nextval();
        tmpx = atof(a.getval());
        if(tmpx < MINX || tmpx > MAXX){
                cout << "X out of bounds" << endl;
                return 0;
        }

        // Pop y value
        a.nextval();
        tmpy = atof(a.getval());
        if(tmpy < MINY || tmpy > MAXY){
                cout << "y out of bounds" << endl;
                return 0;
        }

        // Pop s value
        a.nextval();
        tmps = atof(a.getval());
        if(tmps <= 0){
                cout << "triangle cannot have side 0" << endl;
               return 0;
        }

        Triangle *t = new Triangle(tmpx, tmpy, tmps);
        assert(t != 0);

        //Pop fill value
        a.nextval();
        tmpfill = a.getval()[0];
        t->setfill(tmpfill);

        return t;
}

// Constructor
Triangle::Triangle(float a, float b, float c)
        : Point(a,b)
{ side = c > 0 ? c : 0; }

// Get side
float Triangle::gets() const { return side; }

// Draw
void Triangle::draw() const
{
        cout << "Trinagle: " << endl;
        cout << "Anchor: ";
        Point::draw();
        cout << endl << "Side: " << gets() << endl;
}

#include <iostream.h>
#include "tri.h"
#include "args.h"
#include "shape.h"

main()
{
        Args &a = Triangle::getargs();
        Shape *s;
        char val[5];

        for(int i = a.getlblcnt(); i > 0; i--){
                cout << a.getlbl();
                cin >> val;
                a.addval(val);
                a.nextlbl();
        }

        s = Triangle::makeinstance(a);
        s->draw();

        return 0;
}