I couple of days ago I came across an Ants and Doodlebugs simulator here on DIC, The author said he had a couple of errors but didn;t state what it was, so i tried to do it, but couldn't get it to work, the project compiles, but when I try to build it, it give me 4 errors
[quote]
--------------------Configuration: main - Win32 Debug--------------------
Linking...
main.obj : error LNK2001: unresolved external symbol "public: void __thiscall World::step(void)" (?step@World@@QAEXXZ)
main.obj : error LNK2001: unresolved external symbol "public: void __thiscall World::display(void)" (?display@World@@QAEXXZ)
main.obj : error LNK2001: unresolved external symbol "public: __thiscall World::World(void)" (??0World@@QAE@XZ)
Debug/main.exe : fatal error LNK1120: 3 unresolved externals
Error executing link.exe.

main.exe - 4 error(s), 0 warning(s)
[\quote]
any help is appreciated



here's .cpp
[code]

//*******************CONSTRUCTORS!!!***********************************
Organism::Organism(int posX, int posY, Organism *array[][20])
:level(0), x(posX), y(posY), moved(false){
//Deliberately Empty
}//End Constructor

Ant::Ant(int posX, int posY, Organism *array[][20])
:Organism(posX, posY, array){
//Deliberitaly empty
}//End Constructor

Doodlebugs::Doodlebugs(int posX, int posY, Organism *array[][20])
:Organism(posX, posY, array){
//Deliberately Empty
}//End Constructor


//construct grid
World::World(){
for(int i=0; i<=19; i++){
for(int j=0; j<=19; j++){
array[i][j]=NULL;
}
}
fill();
}//end world


//*****************END CONSTRUCTORS!!!!*******************************

//fill the world with ants and doodlebugs
void World::fill(){
int moveX, moveY;
srand(time(NULL));
for(int NoDB=0; NoDB<=5; NoDB++){//NoDB=number of dooodlebugs
do{
moveX=rand()%20;
moveY=rand()%20;
}while(array[moveX][moveY]!=NULL);
array[moveX][moveY]=new Doodlebugs(moveX, moveY, array);
}//end for
for(int NoAnt=0; NoAnt<=100; NoAnt++){
do{
moveX=rand()%20;
moveY=rand()%20;
}while(array[moveX][moveY]!=NULL);
array[moveX][moveY]=new Ant(moveX, moveY, array);
}//end for

}//end World::fill()

void World::moveReset(){
for(int i=0; i<=19; i++){
for(int j=0; j<=19; j++){
if(array[i][j]!=NULL){
array[i][j]->moved=false;
}//end if
}//end for
}//end for
}//end moveReset

void World::display(){
for(int i=0; i<=19; i++){
for(int j=0; j<=19; j++){
if(array[i][j]!=NULL){
cout<<array[i][j]->getSymbol();
}
else{
cout << " ";
}

}
cout<<endl;
}
//cout << "Displayed" << endl;
}



void World::step(){
for(int i=0; i<=19; i++){
for(int j=0; j<=19; j++){
if(array[i][j] != NULL && array[i][j]->getSymbol() == 'X'){
array[i][j]->move();
}
}
}
for(int a=0; a<=19; a++){
for(int b=0; b<=19; b++){
if(array[a][b]!=NULL && array[a][b]->getSymbol() == 'O'){
array[a][b]->move();
}
}
}
display();
moveReset();
//cout << "Stepped" << endl;
}
//End World creation and population




//Start of move
void Ant::move(){
cout<<"Ant moved:\n";
cout<<x<<" "<<y<<endl;
int changeX, changeY;
level++;
srand(time(NULL));

do{
changeX=rand()%3-1;
changeY=rand()%3-1;
}while(changeX!=changeY);
if (x + changeX <= 19 && x + changeX>=0
&& y + changeY <= 19 && y + changeY>=0
&& changeX!=-changeY
&& world[x+changeX][y+changeY]==NULL
&& moved == false)
{
world[x + changeX][y + changeY] = world[x][y];
world[x][y] = NULL;
x = x + changeX;
y = y + changeY;
}
if (level >= 3){
breed();
}
moved = true;
}//end Ant::move


//Start breeding ants after 3 moves
void Ant::breed(){
cout<<"Ants breed after 3 moves...\n";
for(int i=-1; i<2; i++){
for(int j=-1; j<2; j++){
if (x+i<=19 && y+j<=19
&& x+i>=0 && y+j>=0
&& i!=j && i!=-j
&& world[x+i][y+j]==NULL){
world[x+i][y+j]=new Ant((x+i), (y+j), world);
level=0;
i=2;
j = 2;
}//end if
}//end for
}//end for
}//end breed()


//Ants represented by O
char Ant::getSymbol(){
return 'O';
}

void Doodlebugs::move(){
cout<<"Moving Doodlebugs\n";
cout<<x<<" "<<y<<endl;
int changeX, changeY;//the change in axis
level++;
hunger++;//after 3 moves the doodlebug will starve

bool hasMoved=false;
for(int i=-1; i<2; i++){
for(int j=-1; j<2; j++){
if (x+i >= 0 && y+j >= 0
&& x+i<=19 && y+j<=19
&& i!=j && i!=-j
&& world[x+i][y+j]!=NULL
&& world[x+i][y+j]->getSymbol()=='O'
&& moved == false)
{
delete world[x+i][y+j];
world[x+i][y+j]=world[x][y];
world[x][y]=NULL;
x=x+i;
y=y+j;
i=2;
j=2;
hunger=0;
hasMoved=true;
}
}
}
srand(time(NULL));
do{
changeX = rand() % 3 - 1;
changeY = rand() % 3 - 1;
}while(changeX!=changeY);

if(x+changeX<=19 && x+changeX>=0
&& y+changeY<=19 && y+changeY>=0
&& changeX!=-changeY
&& world[x+changeX][y+changeY]==NULL
&& hasMoved==false
&& moved==false){

world[x + changeX][y + changeY] = world[x][y];
world[x][y] = NULL;
x = x + changeX;
y = y + changeY;
}//end if

if (hunger >= 3){//if doodlebug hasn't eaten after 3 time steps, starve
starve();
}//end if
else if (level >= 8){//afetr 8 time steps. breed
breed();
}//end if
moved = true;
}//End doodlebug move


void Doodlebugs::breed(){
cout << "Doodlebug breeding..."<<endl;
for(int i=-1; i<2; i++){
for(int j=-1; j<2; j++){
if(x+i<=19 && y+j<=19
&& x+i>=0 && y+j>=0
&& i!=j && i!=-j
&& world[x+i][y+j]==NULL)
{
world[x+i][y+j]=new Doodlebugs((x+i), (y+j), world);
level=0;
i=2;
j=2;
}//end if
}//end for
}//end for
}//End doodlebug breed


void Doodlebugs::starve(){
cout << "Doodlebug starved" << endl;
delete world[x][y];
world[x][y]==NULL;
}

char Doodlebugs::getSymbol()
{
return 'X';
}
[\code]