Question

所以我试图通过执行以下操作来创建2D数组：

unsigned char seqA[] = {1, 2, 3, 4, 5, 1, 2, 3, 4, 5};
unsigned char seqB[] = {1, 2, 3, 4, 4, 1, 2, 3, 4, 4};
unsigned char seqC[] = {3, 2, 1, 5, 4, 3, 2, 1, 5, 4};
unsigned char seqD[] = {1, 1, 2, 2, 3, 3, 4, 4, 5, 5};
unsigned char seq[][10] = {seqA, seqB, seqC, seqD};

我尝试这样做会收到很多错误：

Warning 1   missing braces around initializer [-Wmissing-braces]    C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Warning 2   (near initialization for 'seq[0]') [-Wmissing-braces]   C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Warning 3   initialization makes integer from pointer without a cast [enabled by default]   C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Warning 4   (near initialization for 'seq[0][0]') [enabled by default]  C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Error   5   initializer element is not computable at load time  C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Error   6   (near initialization for 'seq[0][0]')   C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Warning 7   initialization makes integer from pointer without a cast [enabled by default]   C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Warning 8   (near initialization for 'seq[0][1]') [enabled by default]  C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Error   9   initializer element is not computable at load time  C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Error   10  (near initialization for 'seq[0][1]')   C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Warning 11  initialization makes integer from pointer without a cast [enabled by default]   C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Warning 12  (near initialization for 'seq[0][2]') [enabled by default]  C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Error   13  initializer element is not computable at load time  C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Error   14  (near initialization for 'seq[0][2]')   C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Warning 15  initialization makes integer from pointer without a cast [enabled by default]   C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Warning 16  (near initialization for 'seq[0][3]') [enabled by default]  C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Error   17  initializer element is not computable at load time  C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3
Error   18  (near initialization for 'seq[0][3]')   C:\Users\Jonathan\Documents\Atmel Studio\6.2\GccApplication3\GccApplication3\GccApplication3.c  135 1   GccApplication3

我做错了什么？

Answer 1

seq是char类型的数组，您尝试使用address to char进行初始化。

替换

unsigned char seq[][10] = {seqA, seqB, seqC, seqD};

与

unsigned char* seq[] = {seqA, seqB, seqC, seqD};

现在，如果您想阅读seqA的第3个元素，请使用：

*(seq[0] +2)或seq[0][2]

Answer 2

除非有特定的理由来命名各行，否则最有效（而且，在我看来，最清楚）的事情将是

static const unsigned char seq[][10] =
  { {1, 2, 3, 4, 5, 1, 2, 3, 4, 5},
    {1, 2, 3, 4, 4, 1, 2, 3, 4, 4},
    {3, 2, 1, 5, 4, 3, 2, 1, 5, 4},
    {1, 1, 2, 2, 3, 3, 4, 4, 5, 5} };

我还添加了const，如果数据非常稳定，可以帮助优化器在某些情况下做得更好，static就可以明确seq仅在该文件中使用（如果是这种情况）。

如果seq仅在一个特定函数中使用，则可以通过将其移动到该函数中来进一步使用它。在这种情况下，您肯定需要static，因为编译器必须生成代码才能将值放在堆栈上。

使用指针解决方案，每次访问都会有四个额外的指针和一个额外的指针解除引用。

C：无法在Atmel Studios中使用1D阵列初始化2D阵列

2 个答案: