Visual Studio中的ASCII字符看起来很奇怪

问题描述

我当时正在用代码块编码c，并且由于它倾向于更好地编译程序，所以想转到Visual Studio，但是由于某种原因，在代码块中显示数字很好的ascii值似乎给了我奇怪的结果在vs中，这是他们的样子的片段：

由于每个平台上的代码完全相同，这使我相信我忽略了int相对于已经在代码块中设置的ascii的某些设置。要检查，这是我的代码：

#include <windows.h>

#define WIDTH 18
#define HEIGHT 18
#define BOMBS 50

struct xorshift_state {
    int a;
};

int xorshift(struct xorshift_state *state)
{
    int x = state->a;
    x ^= x << 13;
    x ^= x >> 17;
    x ^= x << 5;
    return state->a = x;
}

void ExpandGrid(int fullGrid[WIDTH][HEIGHT],int kNownGrid[WIDTH][HEIGHT],int blankPos[2])
{
    int neighbors[8][2] = { { 0,1 },{ 1,0 },{ 0,-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] = blankPos[0] + neighbors[blck][0];
        curTile[1] = blankPos[1] + neighbors[blck][1];
        if (curTile[0] > WIDTH - 1 || curTile[1] > HEIGHT - 1 || curTile[0] < 0 || curTile[1] < 0) 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(int argc,char *argv[])
{

    COORD characterBufferSize = { WIDTH,HEIGHT };
    COORD characterPosition = { 0,0 };
    SMALL_RECT consoleWriteArea = { 0,WIDTH - 1,HEIGHT - 1 };
    CHAR_INFO consoleBuffer[WIDTH][HEIGHT];

    HANDLE wHnd = GetStdHandle(-11);
    HANDLE rHnd = GetStdHandle(-10);

    DWORD numEventsRead = 0;
    DWORD numEvents = 0;
    INPUT_RECORD *eventBuffer = { 0 };
    int wait = 1000;

    int startGrid[WIDTH][HEIGHT] = { 0 };
    int kNownGrid[WIDTH][HEIGHT] = { 0 };
    int arrowPos[2] = { 0,0 };
    int bomb[2] = { 0 };
    struct xorshift_state seed = { argc == 2 ? (int)argv[1] : 1 };

    for (int i = 0; i < BOMBS; i++)
    {
        while (startGrid[bomb[0]][bomb[1]] < -1 || bomb[0] <= 0 || bomb[1] <= 0 || bomb[0] >= WIDTH - 1 || bomb[1] >= HEIGHT - 1)
        {
            bomb[0] = (xorshift(&seed) % WIDTH - 1) + 1;
            bomb[1] = (xorshift(&seed) % HEIGHT - 1) + 1;
        }

        startGrid[bomb[0]][bomb[1]] = -9;

        startGrid[bomb[0] + 1][bomb[1] + 1]++;
        startGrid[bomb[0] + 1][bomb[1]]++;
        startGrid[bomb[0]][bomb[1] + 1]++;
        startGrid[bomb[0] - 1][bomb[1] + 1]++;
        startGrid[bomb[0]][bomb[1] - 1]++;
        startGrid[bomb[0] + 1][bomb[1] - 1]++;
        startGrid[bomb[0] - 1][bomb[1] - 1]++;
        startGrid[bomb[0] - 1][bomb[1]]++;
    }


    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 = 0;
                }

                if (arrowPos[0] == x && arrowPos[1] == y)
                {
                    consoleBuffer[x][y].Attributes = BACKGROUND_RED | BACKGROUND_BLUE | BACKGROUND_GREEN;
                }
            }
        }

        WriteConsoleOutput(wHnd,*consoleBuffer,characterBufferSize,characterPosition,&consoleWriteArea);

        numEvents = 0;
        numEventsRead = 0;
        GetNumberOfConsoleInputEvents(rHnd,&numEvents);

        if (numEvents)
        {
            eventBuffer = malloc(sizeof(INPUT_RECORD) * numEvents);
            ReadConsoleInput(rHnd,eventBuffer,numEvents,&numEventsRead);
        }

        if (numEventsRead && wait <= 0)
        {
            wait = 1000;
            switch (eventBuffer[0].Event.KeyEvent.wVirtualKeyCode)
            {
            case 38:
                arrowPos[0]--;
                break;
            case 40:
                arrowPos[0]++;
                break;
            case 37:
                arrowPos[1]--;
                break;
            case 39:
                arrowPos[1]++;
                break;
            case 13:
                ExpandGrid(startGrid,arrowPos);
                break;
            }
        }

        wait--;
    }
}

解决方法

这不符合您的预期：

bomb[0] = (xorshift(&seed) % WIDTH - 1) + 1;

从此之后开始使用此计算值，您似乎希望它返回[1，WIDTH-2]范围内的值。

但是：

operator precedence表示(foo % WIDTH - 1) + 1与((foo % WIDTH) - 1) + 1相同。就是通过再次添加1来抵消减去的1。
left-shifting negative values（就像您在种子为负值时变成xorshift时可能要做的那样）具有undefined behavior：即。任何事情都可能发生。
right-shifting negative values（就像您在种子为负值时变成xorshift时可能要做的那样）具有implementation defined behavior：即。它的行为可能有所不同，具体取决于编译器等。
modulo operations on negative values定义明确，将导致另一个负值。

考虑到所有这些问题，我不奇怪您看到奇怪的事情发生了。您不仅没有适当地限制计算值的范围，而且还是实现定义和未定义行为的受害者。

代码中可能还存在其他问题，但我将从这些问题开始。

ascii ascii c visual-studio