Reduce size of c program without optimizing compiler - c

Question

Im trying to make a minesweeper game in c which is compact enough to fit into a qr code, like some other people have done with snake. As it stands, my program needs to be around 2.98 KB and is currently 58KB.
Before I move on to trying to make some compiler magic happen, I wanted to know how could refine my code pre-compiler. Is my approach workable, would it have to be completely different, or is fitting the minesweeper program into that small of a size impossible without using assembly? My code can be seen here:
#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#define WIDTH 100
#define HEIGHT 100
#define BOMBS 799
#define KEY_UP 72
#define KEY_DOWN 80
#define KEY_LEFT 75
#define KEY_RIGHT 77
HANDLE wHnd;
HANDLE rHnd;
void SetGrid(int grid[WIDTH][HEIGHT])
{
int bomb[2] = { abs(rand() % WIDTH-1) + 1,
abs(rand() % HEIGHT-1) + 1 };
for (int i = 0; i < BOMBS; i++)
{
while (grid[bomb[0]][bomb[1]] < -1 || bomb[0] == 0 || bomb[1] == 0 || bomb[0] >= WIDTH-1 || bomb[1] >= HEIGHT-1)
{
bomb[0] = abs(rand() % WIDTH-1) + 1;
bomb[1] = abs(rand() % HEIGHT-1) + 1;
}
grid[bomb[0]][bomb[1]] = -9;
grid[bomb[0] + 1][bomb[1] + 1]++;
grid[bomb[0] + 1][bomb[1]]++;
grid[bomb[0]][bomb[1] + 1]++;
grid[bomb[0] - 1][bomb[1] + 1]++;
grid[bomb[0]][bomb[1] - 1]++;
grid[bomb[0] + 1][bomb[1] - 1]++;
grid[bomb[0] - 1][bomb[1] - 1]++;
grid[bomb[0] - 1][bomb[1]]++;
}
}
void ExpandGrid(int fullGrid[WIDTH][HEIGHT], int knownGrid[WIDTH][HEIGHT], int blankPos[2])
{
int neighbors[8][2] = {{0,1}, {1,0}, {1,1},
{0,-1}, {-1,0},
{-1,-1},{-1,1},{1,-1}};
int curTile[2];
knownGrid[blankPos[0]][blankPos[1]] = 1;
if(fullGrid[blankPos[0]][blankPos[1]] != 0) return;
for(int blck = 0; blck < 8; ++blck)
{
curTile[0] = abs(blankPos[0]+neighbors[blck][0]);
curTile[1] = abs(blankPos[1]+neighbors[blck][1]);
if(curTile[0] > WIDTH-1 || curTile[1] > HEIGHT-1) continue;
if(fullGrid[curTile[0]][curTile[1]] == 0 && knownGrid[curTile[0]][curTile[1]] == 0)
{
knownGrid[curTile[0]][curTile[1]] = 1;
ExpandGrid(fullGrid, knownGrid, curTile);
}
else if(fullGrid[curTile[0]][curTile[1]] > 0) knownGrid[curTile[0]][curTile[1]] = 1;
}
}
int main(void)
{
SMALL_RECT windowSize = { 0, 0, WIDTH - 1, HEIGHT - 1 };
COORD characterBufferSize = { WIDTH, HEIGHT };
COORD characterPosition = { 0, 0 };
SMALL_RECT consoleWriteArea = { 0, 0, WIDTH - 1, HEIGHT - 1 };
CHAR_INFO consoleBuffer[WIDTH][HEIGHT];
wHnd = GetStdHandle(STD_OUTPUT_HANDLE);
rHnd = GetStdHandle(STD_INPUT_HANDLE);
SetConsoleTitle("Minesweeper!");
SetConsoleWindowInfo(wHnd, TRUE, &windowSize);
srand((unsigned int)time(NULL));
int startGrid[WIDTH][HEIGHT] = { 0 };
int knownGrid[WIDTH][HEIGHT] = { 0 };
SetGrid(startGrid);
int startCoord[2] = {0, 0};
int arrowPos[2] = {0, 0};
ExpandGrid(startGrid, knownGrid, startCoord);
while(1)
{
if (arrowPos[0] > WIDTH-1) arrowPos[0] = WIDTH-1;
if (arrowPos[0] < 0) arrowPos[0] = 0;
if (arrowPos[1] > HEIGHT-1) arrowPos[1] = HEIGHT-1;
if (arrowPos[1] < 0) arrowPos[1] = 0;
for (int x = 0; x < WIDTH; ++x)
{
for (int y = 0; y < HEIGHT; ++y)
{
if (knownGrid[x][y] == 1)
{
if (startGrid[x][y] > 0)
{
consoleBuffer[x][y].Char.AsciiChar = '0' + startGrid[x][y];
consoleBuffer[x][y].Attributes = FOREGROUND_GREEN | FOREGROUND_INTENSITY;
}
else
{
consoleBuffer[x][y].Char.AsciiChar = 'o';
consoleBuffer[x][y].Attributes = (startGrid[x][y] < 0 ? FOREGROUND_RED : FOREGROUND_BLUE) | FOREGROUND_INTENSITY;
}
}
else
{
consoleBuffer[x][y].Char.AsciiChar = 00;
consoleBuffer[x][y].Attributes = FOREGROUND_BLUE | FOREGROUND_INTENSITY;
}
if(arrowPos[0] == x && arrowPos[1] == y)
{
consoleBuffer[x][y].Attributes = BACKGROUND_RED | BACKGROUND_BLUE | BACKGROUND_GREEN;
}
}
}
WriteConsoleOutputA(wHnd, consoleBuffer, characterBufferSize, characterPosition, &consoleWriteArea);
switch(getch())
{
case KEY_UP:
arrowPos[0]--;
break;
case KEY_DOWN:
arrowPos[0]++;
break;
case KEY_LEFT:
arrowPos[1]--;
break;
case KEY_RIGHT:
arrowPos[1]++;
break;
case '\r':
ExpandGrid(startGrid, knownGrid, arrowPos);
break;
}
}
}

Answer 1

Reducing from 58K to 3K is a pretty big ask.
A few ideas:
Examine the libraries that are linked in during your build process, and reduce those to the bare minimum; Eliminate calls to library functions that you may be able to write yourself.
Possibly use shorter types. Do you need int? Can you use a byte (char) or a short instead?
Consider what parts of windows.h and stdlib.h you really need.