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Adding last element of one list to the end of another

Melchoire (9)
I have 2 global list variables declared like so:
list<Rectangle> pegA;
list<Rectanlge> pegB;
rectangle is a class I made on my own.
During a function I want to add the last element of pegB to the end of pegA. Then remove that last element. This is how I'm doing it:
pegA.push_back(pegB.back());
pegB.pop_back();

But I get this error for push_back:
"error C2663: 'std::vector<_Ty,_Alloc>::back' : 2 overloads have no legal conversion for 'this' pointer"
and this one for pop:
error C2662: 'std::vector<_Ty,_Alloc>::pop_back' : cannot convert 'this' pointer from 'std::vector' to 'std::vector<_Ty,_Alloc> &'

What am I doing wrong?
Disch (13742)
Other than the misspelling of 'Rectanlge' I see nothing wrong with the snippit you posted.

Can you paste the actual code? It doesn't have to be all of it just these two things:

1) The lines declaring your global pegA and pegB objects

2) The function with your push_back / pop_back lines.
Melchoire (9)
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#include <iostream>
#include "Rectangle.h"
#include "Colour.h"
#include <list>
#include "EasyBMP.h"
#include "DisplayBackground.h"

void towers(int numDiscs, int presentPeg, int tempPeg, int toPeg);
void DisplayStep();
void ExecuteStep(int from, int to);

list<Rectangle> pegA;
list<Rectanlge> pegB;
list<Rectangle> pegC;
int curStep;
int reqStep;
void DisplayStep();

void main(void)
{
	int n = 0;
	int step = 0;
	int h = 800;
	int w = 600;
	int wDisc = 0;
	int xLoc = 0;
	int yLoc = 0;

	Colour blue = Colour(0,0,255,255);
	Colour green = Colour(0,255,0,255);
	BMP img;
	DisplayBackground(img,green,w,h);

	//prompt the user for the number of pegs
	cout << "Enter number of pegs: " << endl;
	cin >> n;
	cout << "Which step would you like displayed?" << endl;
	cin >> reqStep;

	Rectangle Rtemp;

	//initialize the first peg
	for(int i = 0; i < n; i++)
	{
		wDisc = (int)400*pow(0.8,i);//exponential function
		xLoc = (w-wDisc)/2;
		yLoc = 800-(25*(i+1));
		Rtemp.SetXLocation(xLoc);
		Rtemp.SetYLocation(yLoc);
		Rtemp.SetWidth(wDisc);
		Rtemp.SetHeight(25);
		Rtemp.SetColour(blue);

		pegA.push_back(Rtemp);
		Rtemp.RectangleDisplay(img);
	}
	img.WriteToFile("C:\\Users\\Dave\\Documents\\bitfile.bmp");
	towers(n, 1, 2, 3);

}


void towers(int numDiscs, int presentPeg, int tempPeg, int toPeg)
{
	if(numDiscs > 0)
	{
		curStep++;
		towers(numDiscs-1, presentPeg, toPeg, tempPeg);
		cout << "Move disc from Peg#" << presentPeg << " to Peg#" << toPeg << endl;
		ExecuteStep(presentPeg, toPeg);
		if(curStep==reqStep)
		{
			DisplayStep();
		}
		towers(numDiscs-1, tempPeg, presentPeg, toPeg);
	}
}

void ExecuteStep(int from, int to)
{
	if(from==1 && to==2)
	{
		pegB.push_back(pegA.back());
		pegA.pop_back();
	}
	else if(from==1 && to==3)
	{
		pegC.push_back(pegA.back());
		pegA.pop_back();
	}
	else if(from==2 && to==3)
	{
		pegC.push_back(pegB.back());
		pegB.pop_back();
	}
	else if(from==2 && to==1)
	{
		pegA.push_back(pegB.back());
		pegB.pop_back();
	}
	else if(from==3 && to==1)
	{
		pegA.push_back(pegC.back());
		pegC.pop_back();
	}
	else if(from==3 && to==2)
	{
		pegB.push_back(pegC.back());
		pegC.pop_back();
	}
}

I posted everything just in case. But my errors are coming from the ExecuteStep function.
Disch (13742)
'Rectanlge' is still spelled wrong (see line 13). That might be your problem.. although I would expect that to throw an error different from the one you described.

Also: EW @ void main. main should always return an int.

EDIT: and wait a minute... you're getting errors with std::vector? but you're not even USING std::vector in that code?

wtf?
Last edited on
Melchoire (9)
Actually those were errors from when I tried to use a vector instead. But anyways that spelling error seemed to be causing all the trouble.

But now I'm getting an error on this:
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void DisplayStep()
{
	list<Rectangle>::iterator it;

	for(it = pegA.begin(); it != pegA.end; it++)
	{
		
	}
}

" error C3867: 'std::list<_Ty>::end': function call missing argument list; use '&std::list<_Ty>::end' to create a pointer to member
1> with"

Thanks for help on the other one btw.
Disch (13742)
"function call missing argument list" is confusing compiler speak for "you forgot your parenthesis"

pegA.end should have parenthesis on it, since it's a function call: pegA.end()
Last edited on
Melchoire (9)
Ah I see. That fixed it. Thanks alot. =]
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