Difference between revisions of "C-and-C++/C3/Working-With-2D-Arrays/English"

What is a 2Dimensional array.

We will do this with the help of an example.

Ubuntu Operating System version 11.10,

gcc and g++ Compiler version 4.6.1 on Ubuntu

2-D arrays are stored in a row column matrix.

The left index indicates the row.

The right index indicates the column.

Starting index of a matrix or array in C and C++ is always 0. Here we see a 2dimensional array in a row column matrix. Starting index is 0.

The Syntax for this is:

data-type arr_name[row] and [col];

eg.here we have declared a 2dimensional array num with 2rows and 3columns. int num[2][3];

I have already typed the program.

Let me open it.

In this program we will calculate the sum of the elements of the 2dimensional arrays. Let me explain the code now.

#include <stdio.h>

int main()

int i,j;

int num1[3][4],num2[3][4];

And num2 again with 3rows and 4columns

printf("Enter the elememts of 3X4 array num1\n");

for(i=0; i<3; i++)

for(j=0; j<4; j++)

scanf("%d", &num1[i][j]);

Here we take elements of the matrix num1 as input from the user.

The elements are stored row-wise.

We have considered i for rows and j for columns.

This for loop will check the condition that i runs from 0 to 2.

This for loop will check the condition that j runs from 0 to 3.

printf("Enter the elememts of 3X4 array num2\n");

for(i=0; i<3; i++)

for(j=0; j<4; j++)

scanf("%d", &num2[i][j]);

printf("The 3X4 array num1 is\n");

for(i=0; i<3; i++)

{

for(j=0; j<4; j++)

printf("%3d ", num1[i][j]);

printf("\n");

}

Here %3d is used to align the matrix on the terminal.

printf("The 3X4 array num2 is\n");

for(i=0; i<3; i++)

{

for(j=0; j<4; j++)

printf("%3d ", num2[i][j]);

printf("\n");

}

printf("The sum of num1 and num2 is\n");

for(i=0; i<3; i++)

{

for(j=0; j<4; j++)

printf("%3d ", (num1[i][j] + num2[i][j]));

printf("\n");

}

And display the result

return 0;

Type

gcc array.c -o arr

./arr

gcc space 2d-array.c space -o space arr and Press enter

To execute type,

./arr Now Press enter

Then Enter the values from 12 to 1

Enter the element of 3X4 array num1

I will enter the values now.

Now we can see,

Enter the elements of 3X4 array num2:

I will enter the values.

The output is displayed.

I have already made the program.

I will oepn it and explain.

2d-array.cpp

Note that our file name is 2d-array.cpp

The extension is .cpp.

Let me explain the code now.

include<iostream>

using namespace std

int main()

cout

and

cin

Then we have “cin function.

We use cin to read a line in C++.

/t

Rest of the code is similar to our C code.

Let me clear the prompt.

g++ array.cpp -o arr

Type

./arr

g++ space array.cpp space -o space arr1

Press Enter

To execute type

./arr1

Press Enter

Then Enter the values from 12 to 1

Enter the element of 3X4 array num1

I will enter the values.

Now we see,

Enter the elements of 3X4 array num2:

I will give the values as

The output is displayed.

num1 matrix

num2 matrix

The sum

This brings us to the end of this tutorial.

Come back to our slides

In this turoial we learnt,

To add elements in a 2D array.

To print 2D array.

And

To calculate the sum of 2D array.

Subtract them and find the result.

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