How to pass and return a 3-Dimensional Array in C++?

Last Updated : 21 Jun, 2022

In C++ a 3-dimensional array can be implemented in two ways:

Using array (static)
Using vector (dynamic)

Passing a static 3D array in a function: Using pointers while passing the array. Converting it to the equivalent pointer type.

char ch[2][2][2];
void display(char (*ch)[2][2]) {
. . .
}

Program to pass a static 3D array as a parameter:

C++

// C++ code to demonstrate the above method #include <bits/stdc++.h> using namespace std; // Function to show how to pass // a 3D character array to a function void display(char (*ch)[2][2]) {  for (int i = 0; i < 2; i++) {  for (int j = 0; j < 2; j++) {  for (int k = 0; k < 2; k++) {  cout << "ch[" << i << "][" << j << "]["  << k << "] = " << ch[i][j][k] << endl;  }  }  } } // Driver code int main() {  char ch[2][2][2] = { { { 'a', 'b' }, { 'c', 'd' } },  { { 'e', 'f' }, { 'g', 'h' } } };  // Function call with 3D array as parameter  display(ch);  return 0; }

Output

ch[0][0][0] = a ch[0][0][1] = b ch[0][1][0] = c ch[0][1][1] = d ch[1][0][0] = e ch[1][0][1] = f ch[1][1][0] = g ch[1][1][1] = h

Time Complexity: O(n³)

Auxiliary Space: O(1)

Passing 3D vector (dynamic array): When a vector is passed to a function, it can either be passed by value, where a copy of the vector is stored, or by reference, where the address of the vector is passed.

Pass by value:

void function(vector <vector <vector < char >>> ch) {
. . .
}

Pass by reference (Better):

void function(vector< vector < vector < char>>> &ch) {
. . .
}

Program to pass a dynamic 3D array as a parameter:

C++

// C++ code to demonstrate the initialization // and passing as a parameter (passed as reference) #include <bits/stdc++.h> using namespace std; // Parameter passed as reference void display(vector<vector<vector<char> > >& ch) {  for (int i = 0; i < 2; i++) {  for (int j = 0; j < 2; j++) {  for (int k = 0; k < 2; k++) {  cout << "ch[" << i << "][" << j << "]["  << k << "] = " << ch[i][j][k] << endl;  }  }  } } int main() {  vector<vector<vector<char> > > ch  = { { { 'a', 'b' }, { 'c', 'd' } },  { { 'e', 'f' }, { 'g', 'h' } } };  // Function to call function by passing as parameter  display(ch);  return 0; }

Output

ch[0][0][0] = a ch[0][0][1] = b ch[0][1][0] = c ch[0][1][1] = d ch[1][0][0] = e ch[1][0][1] = f ch[1][1][0] = g ch[1][1][1] = h

Time Complexity: O(n³)

Auxiliary Space: O(1)

Returning a 3D array: A static array cannot be returned from a function in C++. So we have to pass a 3D vector from a function to get the functionality of returning a 3D array.