Difference between revisions of "C-and-C++/C3/Arrays/English"

What is an array.

Declaration of an array.

Initialization of an array.

Few examples on array.

We will also see some common errors and their solutions.

Ubuntu Operating System version 11.04,

gcc and g++ Compiler version 4.6.1 on Ubuntu.

Array is the collection of data or elements of same data-type.

Array index starts from 0.

The first element is stored at index 0.

There are three types of arrays:

1. Single dimensional array.
2. Two dimensional array.
3. Multi-dimensional array.

We will be discussing single dimensional array in this tutorial.

The Syntax for this is:

data-type (name of the array) array-name (and)[size];

eg. char star[5]; Here we have declared an integer array star which contains 5 elements. The array index will start from star0 to star 4.

The Syntax for this is:

data-type (name of the array)array-name[size]={elements};

eg. int star[3]={1,2,3}; Here we have declared an integer element star with size 3. The elements of the array are 1, 2 and 3. Here the index will start from star0 to star 2.

I have already typed the program on the editor.

So, let me open it.

Let me explain the code now.

#include <stdio.h>

int main()

int star[3]={1,2,3};

The elements of the array are 4, 5 and 6.

int sum;

sum = star[0] + star[1] + star[2];

Note that 4 will be stored at index 0. 5 will be stored at index 1 and 6 will be stored at index 2.

printf("The sum is %d\n",sum);

return 0;

Type

gcc array.c -o arr

./arr

gcc space array.c space -o space arr

Press Enter To execute type,

./arr Press Enter

Output

The sum is 15.

int star[3]=1,2,3;

Let us compile as before.

Error

Invalid initializer and Expected identifier or (bracket) '(' before numeric constants.

Let us fix the error. Type the curly bracket here at line no. 4. Now click on Save

Come back to our terminal. Let us compile as before. Let us execute as before. Yes it is working.

Now save the file with an extension .cpp

click on Save

iostream

using namespace std;

The declaration and initialization of an array is same in C++. Hence no need to change anything here.

cout <<

Now delete the comma and type two opening angle brackets. Delete the bracket here. Again type two opening angle brackets and within the double quotes type backslash n.

g++ array.cpp -o arr

Type

./arr

g++ space array.cpp space -o space array1 Here we have array1 because we don't want to overwrite the output parameter array for the file array.c

Now press Enter To execute

./arr press Enter

Output

The sum is 15. We can see that it is similar to our C code.

Come back to our program.

Type:

star[1] + star[2] + star[3];

I will type

star[1] + star[2] + star[3]; Click on Save

Come back to our terminal. Let me clear the prompt.

Let us execute as before.

Output

This is because array index starts from 0.

star[1]

We can see here the array index starts from 1.

Hence it is giving an error.

Type 0 here 1 and 2. Click on Save

Come back to our terminal. Let us compile as before. execute as before.

Yes it is working.

Now we will go back to our slides.

In this tutorial we learned,

Arrays.

To declare Single Dimensional Array.

To initialize Single Dimensional Array.

eg. int star[3]={4,5,6}

To add the elements of an array.

eg. sum = star[0] + star[1] + star[2];

Write a program to calculate the difference of the elements stored in an array.

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