Chapter13 two-dimensional-array
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The document discusses two-dimensional arrays in C++. It explains that a two-dimensional array is an array of arrays, with elements arranged in rows and columns. It provides examples of declaring, initializing, accessing, inputting, and passing two-dimensional arrays as parameters to functions. It also gives examples of functions that perform operations on two-dimensional arrays, such as addition, multiplication, finding row/column sums, diagonal sums, and transposing the array.
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Two Dimensional Array
It is a collection of data elements of same data type arranged in rows and
columns (that is, in two dimensions).
Declaration of Two-Dimensional Array
Type arrayName[numberOfRows][numberOfColumn];
For example,
int Sales[3][5];
Initialization of Two-Dimensional Array
An two-dimensional array can be initialized along with declaration. For two-
dimensional array initialization, elements of each row are enclosed within curly
braces and separated by commas. All rows are enclosed within curly braces.
int A[4][3] = {{22, 23, 10},
{15, 25, 13},
{20, 74, 67},
{11, 18, 14}};](https://image.slidesharecdn.com/chapter13-two-dimensional-array-150809074111-lva1-app6891/85/Chapter13-two-dimensional-array-1-320.jpg)
![Referring to Array Elements
To access the elements of a two-dimensional array, we need a pair of indices:
one forthe row position and one for the column position. The format is as simple
as:
name[rowIndex][columnIndex].
Examples:
cout << A[1][2]; //print an array element
A[1][2] = 13; // assign value to an array element
cin >> A[1][2]; //input element
Using Loop to input an Two-Dimensional Array from user
int mat[3][5], row, col ;
for (row = 0; row < 3; row++)
for (col = 0; col < 5; col++)
cin >> mat[row][col];
Arrays as Parameters
Two-dimensional arrays can be passed as parameters to a function, and they
are passed by reference. When declaring a two-dimensional array as a formal
parameter, we can omit the size of the first dimension, but not the second; that
is, we must specify the number of columns. For example:
void print(int A[][3], int N, int M)
In order to pass to this function an array declared as:
int arr[4][3];
we need to write a call like this:
print(arr);](https://image.slidesharecdn.com/chapter13-two-dimensional-array-150809074111-lva1-app6891/85/Chapter13-two-dimensional-array-2-320.jpg)
![Here is a complete example:
#include <iostream>
using namespace std;
void print(int A[][3], int N, int M)
{
for (R = 0; R < N; R++)
for (C = 0; C < M; C++)
cout << A[R][C];
}
int main ()
{
int arr[4][3] ={{12, 29, 11},
{25, 25, 13},
{24, 64, 67},
{11, 18, 14}};
print(arr,4,3);
return 0;
}
Function to read the array A
void Read(int A[][20], int N, int M)
{
for(int R = 0; R < N; R++)
for(int C = 0; C < M; C++)
{
cout << "(R<<','<<")?";
cin >> A[R][C];
}
}](https://image.slidesharecdn.com/chapter13-two-dimensional-array-150809074111-lva1-app6891/85/Chapter13-two-dimensional-array-3-320.jpg)
![Function to display content of a two dimensional array A
void Display(int A[][20], int N, int M)
{
for(int R = 0;R < N; R++)
{
for(int C = 0; C < M; C++)
cout << setw(10) << A[R][C];
cout << endl;
}
}
Function to find the sum of two dimensional arrays A and B
void Addition(int A[][20], int B[][20], int N, int M)
{
for(int R = 0; R < N; R++)
for(int C = 0;C < M; C++)
C[R][C] = A[R][C] + B[R][C];
}
Function to multiply two dimensional arrays A and B of
order NxL and LxM
void Multiply(int A[][20], int B[][20], int C[][20],int N, int L,
int M)
{
for(int R = 0; R < N; R++)
for(int C = 0; C < M; C++)
{
C[R][C] = 0;
for(int T = 0; T < L; T++)
C[R][C] += A[R][T] * B[T][C];
}
}](https://image.slidesharecdn.com/chapter13-two-dimensional-array-150809074111-lva1-app6891/85/Chapter13-two-dimensional-array-4-320.jpg)
![Function to find & display sum of rows & sum of cols. of array A
void SumRowCol(int A[][20], int N, int M)
{
for(int R = 0; R < N; R++)
{
int SumR = 0;
for(int C = 0; C < M; C++)
SumR += A[R][C];
cout << "Row("<<R<<")=" << SumR << endl;
}
for(int R = 0;R < N; R++)
{
int SumR = 0;
for(int C = 0; C < M; C++)
SumR += A[R][C];
cout << "Row("<<R<<")=" << SumR << endl;
}
}
Function to find sum of diagonal elements of a square matrix A
void Diagonal(int A[][20], int N, int &Rdiag, int &LDiag)
{
for(int I = 0, Rdiag = 0; I < N; I++)
Rdiag += A[I][I];
for(int I = 0, Ldiag = 0; I < N; I++)
Ldiag += A[N-I-1][I];
}
Function to find out transpose of a two dimensional array A
void Transpose(int A[][20], int B[][20], int N, int M)
{
for(int R = 0; R < N; R++)
for(int C = 0;C < M; C++)
B[R][C] = A[C][R];
}](https://image.slidesharecdn.com/chapter13-two-dimensional-array-150809074111-lva1-app6891/85/Chapter13-two-dimensional-array-5-320.jpg)
Chapter13 two-dimensional-array
- 1. www.cppforschool.com Two Dimensional Array It is a collection of data elements of same data type arranged in rows and columns (that is, in two dimensions). Declaration of Two-Dimensional Array Type arrayName[numberOfRows][numberOfColumn]; For example, int Sales[3][5]; Initialization of Two-Dimensional Array An two-dimensional array can be initialized along with declaration. For two- dimensional array initialization, elements of each row are enclosed within curly braces and separated by commas. All rows are enclosed within curly braces. int A[4][3] = {{22, 23, 10}, {15, 25, 13}, {20, 74, 67}, {11, 18, 14}};
- 2. Referring to Array Elements To access the elements of a two-dimensional array, we need a pair of indices: one forthe row position and one for the column position. The format is as simple as: name[rowIndex][columnIndex]. Examples: cout << A[1][2]; //print an array element A[1][2] = 13; // assign value to an array element cin >> A[1][2]; //input element Using Loop to input an Two-Dimensional Array from user int mat[3][5], row, col ; for (row = 0; row < 3; row++) for (col = 0; col < 5; col++) cin >> mat[row][col]; Arrays as Parameters Two-dimensional arrays can be passed as parameters to a function, and they are passed by reference. When declaring a two-dimensional array as a formal parameter, we can omit the size of the first dimension, but not the second; that is, we must specify the number of columns. For example: void print(int A[][3], int N, int M) In order to pass to this function an array declared as: int arr[4][3]; we need to write a call like this: print(arr);
- 3. Here is a complete example: #include <iostream> using namespace std; void print(int A[][3], int N, int M) { for (R = 0; R < N; R++) for (C = 0; C < M; C++) cout << A[R][C]; } int main () { int arr[4][3] ={{12, 29, 11}, {25, 25, 13}, {24, 64, 67}, {11, 18, 14}}; print(arr,4,3); return 0; } Function to read the array A void Read(int A[][20], int N, int M) { for(int R = 0; R < N; R++) for(int C = 0; C < M; C++) { cout << "(R<<','<<")?"; cin >> A[R][C]; } }
- 4. Function to display content of a two dimensional array A void Display(int A[][20], int N, int M) { for(int R = 0;R < N; R++) { for(int C = 0; C < M; C++) cout << setw(10) << A[R][C]; cout << endl; } } Function to find the sum of two dimensional arrays A and B void Addition(int A[][20], int B[][20], int N, int M) { for(int R = 0; R < N; R++) for(int C = 0;C < M; C++) C[R][C] = A[R][C] + B[R][C]; } Function to multiply two dimensional arrays A and B of order NxL and LxM void Multiply(int A[][20], int B[][20], int C[][20],int N, int L, int M) { for(int R = 0; R < N; R++) for(int C = 0; C < M; C++) { C[R][C] = 0; for(int T = 0; T < L; T++) C[R][C] += A[R][T] * B[T][C]; } }
- 5. Function to find & display sum of rows & sum of cols. of array A void SumRowCol(int A[][20], int N, int M) { for(int R = 0; R < N; R++) { int SumR = 0; for(int C = 0; C < M; C++) SumR += A[R][C]; cout << "Row("<<R<<")=" << SumR << endl; } for(int R = 0;R < N; R++) { int SumR = 0; for(int C = 0; C < M; C++) SumR += A[R][C]; cout << "Row("<<R<<")=" << SumR << endl; } } Function to find sum of diagonal elements of a square matrix A void Diagonal(int A[][20], int N, int &Rdiag, int &LDiag) { for(int I = 0, Rdiag = 0; I < N; I++) Rdiag += A[I][I]; for(int I = 0, Ldiag = 0; I < N; I++) Ldiag += A[N-I-1][I]; } Function to find out transpose of a two dimensional array A void Transpose(int A[][20], int B[][20], int N, int M) { for(int R = 0; R < N; R++) for(int C = 0;C < M; C++) B[R][C] = A[C][R]; }