C ++：创建包含3维数组元素的1维数组

Question

I'm trying to create 1-dimensional array containing elements from 3-dimensional array

For example:

float array[4][3][6];

for (int j = 0; j < 3; j++) {
  for (int k = 0; k < 6; k++) {
     temp[4] = {array[0][j][k],array[1][j][k],array[2][j][k],array[3][j][k]};
  }
}

However when I compiled the code, it returned an error as follow for line 4: error: expected primary-expression before '{' token and error: expected ;' before '{' token`

Does anyone know what went wrong here?

This method worked before, but I'm really stumped at what happening now.

Thank you.

Answer 1

   // create 1d array with 3d property's 
   float array[width * height * depth];

    // get and set functions
    float get(int x,int y,int z)
    {
         return array[x + (y * width)+ (z * width * height)];
    }
    void set(float value,int x,int y,int z)
    {
         array[x + (y * width)+ (z * width * height)] = value;
    }


//iterate over the array
for(int z = 0; z < depth; ++z)
  for(int y = 0; y < height; ++y)
    for(int x = 0; x < width ; ++x)
        get(x,y,z);

Answer 2

The {} can only be use for initialization at compile time and need to be constant.

You would need to use float temp[4]; and then in your loop:

temp[0] = array[0][j][k]
temp[1] = array[1][j][k]
temp[2] = array[2][j][k]
temp[3] = array[3][j][k]

This will make your code compile but you know that in the end, only 4 component of your 3-d array will remain and those will be

array[0][2][5],array[1][2][5],array[2][2][5],array[3][2][5]

Unless you didn't show all the code, you might as well skip the 2 loops and just affect them directly.

Answer 3

I think you can use something like this:

float array[4][3][6];

for (int j = 0; j < 3; j++) {
   for (int k = 0; k < 6; k++) {
      for (int i=0; i < 4; i++ )
         temp[i] = array[i][j][k];
   }
}