[英]How to create a variable sized array, pass a variable 2d array to a function and return another 2d array?
如何創建尺寸可變的2d數組,傳遞該變量數組並返回不同尺寸的2d新數組? 我已經為此工作了幾個小時,但找不到解決方案。 我設法為PGM圖像創建了一個像素值數組,但是現在我試圖“旋轉”該數組,但這變得異常復雜,因為我的編譯器不允許我聲明可變大小的對象。謝謝對於那些回答的人來說非常重要。
這是調用該函數的語句。 有人告訴我使用malloc,因為您無法創建大小可變的數組。
char *SpunArray = malloc(image->x * image->y * sizeof(PGMPixel));
SpunArray = Rotate90Array(image->x, image->y, CreatedArray);
這是功能:
//char * Rotate90Array(int x, int y, char *array[x][y] )
char * Rotate90Array(int x, int y, char *array )
{
printf("\nLine 179");
// These have to be swapped because the image is being rotated
char *RotatedArray = malloc(x * y * sizeof(char));
printf("\nLine 182");
int u = x - 1;
int v = y - 1;
int i = 0;
int j = 0;
printf("\nLine 187");
char *ptr;
printf("\nLine 189");
for (i = 0; i < x; i++)
{
printf("\nLine 192");
*ptr = RotatedArray[i];
printf("\nLine 194");
for (j = 0; j < y; j++)
{
printf("\nLine 197");
// *ptr = *(array[u-j][i]);
*(ptr+((j*x)+(u-i))) = *(array+((i*y)+j));
printf("\nLine 200");
ptr++;
printf("\nLine 202");
}
}
printf("\nLine 205");
return RotatedArray;
}
我正在使用MingGW gcc和Windows 8(如果有幫助)。
您有內存泄漏。 為什么要創建兩個數組而不是一個?
這樣做:
char *SpunArray = malloc(image->x * image->y * sizeof(PGMPixel));
Rotate90Array(image->x, image->y, CreatedArray, SpunArray);
void Rotate90Array(int width, int height, char *array, char *RotatedArray)
{
int i = 0;
int j = 0;
for (i = 0; i < width; i++)
{
for (j = 0; j < height; j++)
{
// check this line on correct
RotatedArray[i * height + j] = array[j * width + width - i - 1];
}
}
}
我認為這段代碼可以按預期工作:
char * Rotate90Array(int x, int y, char *array )
{
printf("\nLine 179");
// These have to be swapped because the image is being rotated
char *RotatedArray = malloc(x * y * sizeof(char));
printf("\nLine 182");
int u = x - 1;
int v = y - 1;
int i = 0;
int j = 0;
printf("Line 187\n");
char *ptr;
printf("Line 189\n");
ptr = RotatedArray; //I add this line
for (i = 0; i < x; i++)
{
printf("Line 192\n");
// *ptr = RotatedArray[i]; //I delete this line
printf("Line 194\n");
for (j = 0; j < y; j++)
{
printf("Line 197\n");
// *ptr = *(array[u-j][i]);
*(ptr+((j*x)+(u-i))) = *(array+((i*y)+j));
printf("Line 200\n");
// ptr++; // I delete this line
printf("Line 202\n");
}
}
printf("Line 205\n");
return RotatedArray;
}
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