Problems creating Stack! (arcade game) in C++ - c++

Question

im a beginner amateur in C++ and i recently had the idea to remake the popular arcade game Stack! in the C++ console.
The problem occours when the player has got to place the pad:
the pad places well, but if you make an error it doesn't resize properly (you'll understand better when you'll run the code).
Don't care about the graphic that sometimes bugs, because i can fix that on my own.
Please help me!
Here is the code:
#include <iostream>
#include <stdio.h>
#include <cstdlib>
#include <windows.h>
#include <string>
using namespace std;
bool bDirection = true; /* Bool for the direction:
true = dx, false = sx */
string sPad;
int nPadLenght = 6;
int x = 40, y =21; // Referement tile's position
int nSpeed = 200;
bool loop = true; // main loop
int nScore = 0; // score
int nPlaceX = 40;
int nTileX = 35, nTileY = 20; // Player's actual postition
int nEndTileX, nEndTileY;
void RenderLine(int *x, int *y);
int main();
// Void for the coordinates
void gotoxy (int x, int y){
COORD coord;
coord.X = x ;
coord.Y = y ;
SetConsoleCursorPosition (GetStdHandle(STD_OUTPUT_HANDLE), coord);
}
void Victory(){
x = 10;
y = 4;
Beep(698.5, 300);
Beep(698.5, 100);
Beep(1047, 500);
system("color a");
gotoxy(x,y); cout << "You win!\n\n Score = " << nScore;
system("pause >nul");
}
void PadLenght(int *x){
// Each number is equal to a possible pad lenght
switch (*x){
case 6:
sPad = "[][][]";
nEndTileX = nTileX + 5;
break;
case 5:
sPad = "[][]]";
nEndTileX = nTileX + 4;
break;
case 4:
sPad = "[][]";
nEndTileX = nTileX + 3;
break;
case 3:
sPad = "[][";
nEndTileX = nTileX + 2;
break;
case 2:
sPad = "[]";
nEndTileX = nTileX + 1;
break;
case 1:
sPad = "[";
nEndTileX = nTileX;
break;
}
}
void SwitchDirection(bool *x){
// Switches the bool of the direction
switch (*x){
case true:
*x = false;
break;
case false:
*x = true;
break;
}
}
void Speed(){
// For each line from 500ms to 20ms speed increments of 10ms
if (nSpeed > 20)
nSpeed -= 20;
}
// void for placing the pad
void Place() {
int i = nPlaceX - nTileX;
if (i < 0)
i * -1;
nPadLenght -= i;
}
void collision(){
// Collisions with the border
if (nTileX > 45 || nTileX < 35)
SwitchDirection(&bDirection);
}
void movement(){
int nLastX = nTileX;
// Place the pad if pressing down arrow
if(GetKeyState(VK_DOWN) & 0x8000){
nTileY--;
Place();
Speed();
Beep(698.5, 50);
Beep(880.0, 50);
Beep(1047, 50);
nScore += 10;
Sleep(60);
}
// Movement of the pad
switch (bDirection){
case true:
gotoxy (nLastX, nTileY); cout << " ";
nTileX++;
break;
case false:
gotoxy (nLastX - nPadLenght, nTileY); cout << " ";
nTileX--;
break;
}
}
int main(){
system("color 0");
while (loop = true){
char a = '"';
gotoxy(x,y); cout << a << a << a << a << a << a;
collision();
PadLenght(&nPadLenght);
movement();
gotoxy (nTileX, nTileY); cout << sPad;
Sleep (nSpeed);
if (nScore > 160) {
Victory();
break;
}
}
return 0;
}

Answer 1

Here are some issues I found:
"using namespace std;"
This is bad. This brings in all of the identifier names from the std namespace. The preference is to use the std prefix (e.g. std::cout) or choose from the std namespace, (e.g. using std::cout;).
Global variables
Prefer to not have global variables. Create them in main and pass them to functions.
For example, you have global x and y, and you use x and y as parameters in functions. This may lead to confusion between you, readers and the compilers, as to which variables you are referring to.
Passing by pointer
Prefer not to use pointers.
Pass by value (without pointers) for variables that can fit into a processor's register, like float, double, int, bool and char.
For classes and structures, pass by reference. If you are not modifying the parameter, pass by constant reference.
Don't create functions for simple content
Functions require an overhead to execute, usually at least 3 instructions (save parameters, branch to function, return from function). Some operations can be performed with less statements:
// Switch directions:
direction = ! direction;
If you must use functions, give the compiler the hint that you want them inline. This means that the compiler will paste the content of the function where the function call is made. Some compilers may do this for optimizations, but you have to tell the compiler to optimize.
Boolean switch statements
Switch statements are kind of overkill for Boolean varibles, since there are only 2 outcomes. Common coding guidelines are to use if and else.
'=' in conditional expressions
Remember, one = for assignment, two for comparison.
The language allows for an assignment in a comparison, but most likely, you were not thinking of assignment, but testing for equality.
Declare variables closest to usage
Make life easier on you, the compiler and reader, by declaring variables closest to where they are used. For example, in main, there is a loop variable. As a reader, I have to scroll to the top of your source to find the definition, when a better idea is to declare it in the main function, where it is used.
One variable declaration per line
A common coding guideline is one variable per line. Multiple lines have a negligible effect on the build time. However, this makes modifications easier. And when declaring pointers, reduces injected defects. Let your compiler optimize the code, your task should be write clear (easily readable) and concise code.
Increase the compiler's warning level
Force your compiler to turn on the warning level to its highest level.
Resolve all warnings.
A clean compilation has zero errors and zero warnings.
With compiler warnings at full, you would have noticed some of the issues I have identified.