Searching and sorting arrays in C / C++ How to use multidimensional Arrays in C / C++
In the previous tutorial, we learned about one-dimensional arrays in C / C++. In this tutorial, we will learn about multidimensional arrays in C/C++.
More specifically, we will learn about the structure, declaration and initialization of multidimensional arrays. So, make sure you learn about one-dimensional arrays first.
arrays are used to store data of the same type. Data in multidimensional arrays are stored in row-major order. It consists of rows and columns, depending on what we declare.In this tutorial, we only learn about two types of multidimensional arrays:
- Two-dimensional
arraysin C/C++. - Three-dimensional
arraysin C/C++.
Now let's get started with us !!!
Declare multidimensional array in C / C++
General syntax for declaring multidimensional arrays in C / C++:
data_type array_name[size1][size2]....[sizeN];
Here,
- data_type: This is the data type of the elements that the multidimensional
arraycan store. - array_name: This is the name of the multidimensional
array, it is used to call the multidimensionalarraylater. - [size1] [size2]....[sizeN]: This is the size of the
array, determined by the number of rows and columns that we declare.
Example 1: Declare a two-dimensional array in C / C++.
int two_d[10][20];
Example 2: Declare a three-dimensional array in C / C++.
int three_d[10][20][30];
Size of Multidimensional Arrays:
The size of a multidimensional array is calculated by multiplying the dimensions of the row and column.
Example 3: The size of the two-dimensional array.
The array int number[3][4] can store up to 3 * 4 = 12 (elements).
Example 4: The size of the three-dimensional array.
The array int number[3][4][5] can store up to 3 * 4 * 5 = 60 (elements).
Initialize multidimensional arrays in C / C++
Here, we will learn about how to initialize two-dimensional arrays and three-dimensional arrays.
Initialize a two-dimensional array
Suppose we want to declare a two-dimensional array consisting of elements {1, 2, 3, 4, 5, 6}, as shown below:
Then we have the following ways to initialize.
Method 1:
int number[2][3] = {1, 2, 3, 4, 5, 6};For this method, it is not optimal. Take a look at the second method.
Method 2:
int number[2][3] = {{1, 2, 3}, {4, 5, 6}};Initialize a three-dimensional array
Similar to how to initialize a two-dimensional array, we have an example of three-dimensional array initialization as follows:
Example: Initialize a multidimensional array consisting of elements {3, 4, 2, 3, 0, -3, 9, 11, 23, 12, 23, 2, 13, 4, 56, 3, 5, 9, 3, 5, 5, 1, 4, 9}.
Method 1:
int test[2][3][4] = {3, 4, 2, 3, 0, -3, 9, 11, 23, 12, 23, 2, 13, 4, 56, 3, 5, 9, 3, 5, 5, 1, 4, 9};Method 2:
int test[2][3][4] = {
{ {3, 4, 2, 3}, {0, -3, 9, 11}, {23, 12, 23, 2} },
{ {13, 4, 56, 3}, {5, 9, 3, 5}, {5, 1, 4, 9} }
};Import and export elements in a multidimensional array in C / C++
Here, we take the program that imports and exports the elements in a two-dimensional array as an example. Other types of multidimensional arrays are done similarly.
Example: Use the rand() function to enter random elements in a two-dimensional array. Then display the elements to the screen.
#include <iostream>
using namespace std;
#define ROW 100
#define COL 100
void ImportMulArrays(int mt[][COL], int &m, int &n)
{
srand(time(NULL));
cout << "Enter row number m: ";
cin >> m;
cout << "Enter col number n: ";
cin >> n;
for (int i = 0; i < m; i++)
{
for (int j = 0; j < n; j++)
{
mt[i][j] = rand() % 100;
}
}
}
void ExportMulArrays(int mt[][COL], int m, int n)
{
for (int i = 0; i < m; i++)
{
for (int j = 0; j < n; j++)
{
cout << mt[i][j] << "\t";
}
cout << endl;
}
}
int main()
{
int mt[ROW][COL];
int nRow, nCol;
ImportMulArrays(mt, nRow, nCol);
ExportMulArrays(mt, nRow, nCol);
cout<<"\n--------------------------------\n";
cout<<"This program is posted at learnnc.com";
return 0;
}Output:
Examples of multidimensional array in C / C++
Here, we have basic examples of multidimensional arrays in C / C++.
Example 1: Find the sum of elements by user-entered row or column in a two-dimensional array.
#include <iostream>
using namespace std;
#define ROW 100
#define COL 100
void ImportArrays(int mt[][COL], int &m, int &n);
void ExportArrays(int mt[][COL], int m, int n);
int SumRow(int mt[][COL], int n, int d);
int SumCol(int mt[][COL], int m, int c);
int main()
{
int mt[ROW][COL];
int nRow, nCol;
ImportArrays(mt, nRow, nCol);
ExportArrays(mt, nRow, nCol);
int d;
cout << "Enter row to find of sum: : ";
cin >> d;
cout << "Sum of row "<<d<<": " << SumRow(mt, nCol, d) << endl;
int c;
cout << "Enter col to find of sum: : ";
cin >> c;
cout << "Sum of col "<<c<<": " << SumCol(mt, nRow, c) << endl;
cout<<"\n-------------------------------\n";
cout<<"This program is posted at learnnc.com";
return 0;
}
void ImportArrays(int mt[][COL], int &m, int &n)
{
srand(time(NULL));
cout << "Enter row number m: ";
cin >> m;
cout << "Enter col number m: ";
cin >> n;
for (int i = 0; i < m; i++)
{
for (int j = 0; j < n; j++)
{
mt[i][j] = rand() % 100;
}
}
}
void ExportArrays(int mt[][COL], int m, int n)
{
for (int i = 0; i < m; i++)
{
for (int j = 0; j < n; j++)
{
cout << mt[i][j] << "\t";
}
cout << endl;
}
}
int SumRow(int mt[][COL], int n, int d)
{
int sum(0);
for (int j = 0; j < n; j++)
sum += mt[d][j];
return sum;
}
int SumCol(int mt[][COL], int m, int c)
{
int sum(0);
for (int i = 0; i < m; i++)
sum += mt[i][c];
return sum;
}Output:
Example 2: Find the largest element in a two-dimensional array
#include <iostream>
using namespace std;
#define ROW 100
#define COL 100
void ImportArrays(int mt[][COL], int &m, int &n);
void ExportArrays(int mt[][COL], int m, int n);
int FindMax(int mt[][COL], int m, int n);
int main()
{
int mt[ROW][COL];
int nRow, nCol;
ImportArrays(mt, nRow, nCol);
ExportArrays(mt, nRow, nCol);
int max = FindMax(mt, nRow, nCol);
cout << "Max = " << max << endl;
cout<<"\n-------------------------------\n";
cout<<"This program is posted at learnnc.com";
return 0;
}
void ImportArrays(int mt[][COL], int &m, int &n)
{
srand(time(NULL));
cout << "Enter row number m: ";
cin >> m;
cout << "Enter col number m: ";
cin >> n;
for (int i = 0; i < m; i++)
{
for (int j = 0; j < n; j++)
{
mt[i][j] = rand() % 100;
}
}
}
void ExportArrays(int mt[][COL], int m, int n)
{
for (int i = 0; i < m; i++)
{
for (int j = 0; j < n; j++)
{
cout << mt[i][j] << "\t";
}
cout << endl;
}
}
int FindMax(int mt[][COL], int m, int n)
{
int i, j, max;
max = mt[0][0];
for (i = 0; i < m; i++)
for (j = 0; j < n; j++)
if (mt[i][j] > max)
max = mt[i][j];
return max;
}Output:
Example 3: Initialize and display elements in a multidimensional array
#include <iostream>
using namespace std;
int main()
{
int array[2][3][2] = {
{
{1, 2},
{3, 4},
{5, 6}
},
{
{7, 8},
{9, 10},
{11, 12}
}
};
for (int i = 0; i < 2; ++i) {
for (int j = 0; j < 3; ++j) {
for (int k = 0; k < 2; ++k) {
cout << "array[" << i + 1 << "][" << j + 1 << "][" << k + 1 << "] = " << array[i][j][k] << endl;
}
}
}
cout<<"\n-------------------------------\n";
cout<<"This program is posted at learnnc.com";
return 0;
}
Output:
