分离header.h、main.cpp和implementation.cpp中的代码

Question

I'm trying to separate my code into header.h, main.cpp and implementation.cpp, but I'm not getting it. Can someone help me? I need that separate code in these files, and that the game works properly. I've tried in several ways, but I'm not getting.If I try to run as is, the IDE reports "multiple definition of"

main.cpp

#include<iostream>
#include<conio.h>
#include"implem.cpp"

using namespace std;

int main()
{
    setup();
    while (!gameover) {
        mapa ();
        input ();
        algoritmo ();
}
return 0;
}

header.h

#ifndef HEADER_FLAG
#define HEADER_FLAG

void setup();
void mapa();
void input();
void algoritmo();

#endif

implem.cpp

#include<conio.h>
#include"header.h"
#include<stdlib.h>
#include<time.h>

using namespace std;

bool gameover;
const int width = 20;
const int height = 17;
int x, y, fruitX, fruitY, score;
int tailX[100], tailY[100]; //snake coordinates
int nTail;
enum eDirecton {STOP = 0, LEFT,RIGHT, UP, DOWN}; // Controls

eDirecton dir;

void setup(){
gameover = false;
dir = STOP;
x = width / 2;
y = height / 2;
fruitX = rand() % width;
fruitY = rand() % height; score = 0;
}

void mapa(){
system("cls");

for(int i = 0; i < width+2; i++)
cout << "#";
cout << endl ;

for (int i = 0; i < height ; i++) {
    for (int j = 0; j < width; j++) {
        if (j == 0)
            cout << "#"; //walls
            if (i == y && j == x)
                cout << "*"; // snake tale
            else if (i == fruitY && j == fruitX )
                cout << "%"; // change it to change the fruit
        else {
bool print = false;
    for (int k = 0; k< nTail ; k++) {
        if (tailX [k] == j && tailY [k] == i) {
            cout << "*"; print = true;
}
}   if (!print) cout << " ";
}if (j == width -1)
    cout << "#";
}cout << endl;
}
for (int i = 0; i< width+2; i++)
    cout << "#";
    cout << endl;
    cout << "Score:" << score << endl ;
}

void input()
{

if (_kbhit ()) {
    switch (_getch ()) {
        case 'a':
        dir = LEFT;
        break;

        case 'd':
        dir = RIGHT;
        break;

        case 'w':
        dir = UP;
        break;

        case 's':
        dir = DOWN ;
        break;

        case 'x':
        gameover = true;
        break;
}
}
}

void algoritmo(){
int prevX = tailX [0];
int prevY = tailY [0];
int prev2X, prev2Y;

tailX[0] = x;
tailY[0] = y;

for(int i = 1;i < nTail ; i++) {
    prev2X = tailX[i];
    prev2Y = tailY[i];
    tailX[i] = prevX;
    tailY[i] = prevY;
    prevX = prev2X;
    prevY = prev2Y ;

}

switch (dir) {

    case LEFT:
    x--;
    break;

    case RIGHT:
    x++;
    break;

    case UP:
    y--;
    break;

    case DOWN:
    y++;
    break;

default:

break;

}
if (x >= width) x =0;else if (x <0) x = width -1;
    if (y >= height) y = 0; else if (y < 0) y = height - 1;
        for (int i =0; i< nTail ;i++)
    if (tailX[i] == x && tailY[i] == y)
        gameover = true;
    if (x == fruitX && y == fruitY) {
        score +=10;
        fruitX = rand() % width;
        fruitY = rand() % height;
    nTail ++;
}
}```

Answer 1

I suspect that the multiple definition error is due to the fact that the project has main.cpp and implem.cpp . Since you also #include "implem.cpp" in main, symbols from implem.cpp have two origins, and the linker complains.

Never ever #include an implementation code. The correct way to structure your project is:

// main.cpp
#include "header.h"

int main()
{
    setup();
    while (!gameover) {
        mapa ();
        input ();
        algoritmo ();
    }
    return 0;
}

header.h and implem.cpp should remain as they are.

Notice that you don't need to #include anything else in main , because it doesn't refer to the symbols declared in either iostream or conio.h .

Answer 2

You're #include ing implem.cpp into main.cpp instead of implem.h .

Probably you've also added implem.cpp to the project in your IDE. Then it's compiled on its own, and a second time as included part of main.cpp. When the IDE links the compiled object files, all the stuff in implem.cpp will be doubly defined.