PROGRAMMING WITH C&C++

 PROGRAMMING WITH C&C++ UNIT-2

posted by Madhuri Gongati

Arrays

Arrays are used to store multiple values in a single variable, instead of declaring separate variables for each value.

To create an array, define the data type (like int) and specify the name of the array followed by square brackets [].

To insert values to it, use a comma-separated list, inside curly braces:

int myNumbers[] = {25, 50, 75, 100};

We have now created a variable that holds an array of four integers.

Access the Elements of an Array

To access an array element, refer to its index number.

Array indexes start with 0: [0] is the first element. [1] is the second element, etc.

This statement accesses the value of the first element [0] in myNumbers:

 

Example

int myNumbers[] = {25, 50, 75, 100};

printf("%d", myNumbers[0]);

 

// Outputs 25

Change an Array Element

To change the value of a specific element, refer to the index number:

 

Example

myNumbers[0] = 33;

Example

int myNumbers[] = {25, 50, 75, 100};

myNumbers[0] = 33;

printf("%d", myNumbers[0]);

 

// Now outputs 33 instead of 25

Loop Through an Array

You can loop through the array elements with the for loop.

The following example outputs all elements in the myNumbers array:

 

Example

int myNumbers[] = {25, 50, 75, 100};

int i;

for (i = 0; i < 4; i++) {

  printf("%d\n", myNumbers[i]);

}

Set Array Size

Another common way to create arrays, is to specify the size of the array, and add elements later:

Example:1

// Declare an array of four integers:

int myNumbers[4];

// Add elements

myNumbers[0] = 25;

myNumbers[1] = 50;

myNumbers[2] = 75;

myNumbers[3] = 100;

Example:2

Int myNumber[4]={1,2,3,4};

Example:3

Int myNumber[4];

Printf(“enter array elements”);

Scanf(“%d”,&myNumber[i]);

Types of Array in C

There are two types of arrays based on the number of dimensions it has. They are as follows:

1. One Dimensional Arrays (1D Array)
2. Multidimensional Arrays

1. One Dimensional Array in C

The One-dimensional arrays, also known as 1-D arrays in C are those arrays that have only one dimension.

Syntax of 1D Array in C

datatype array_name [size];

EXAMPLE #include <stdio.h>

 

int main()

{

 

    // creating array of character

    char arr[6] = { 'G', 'e', 'e', 'k', 's', '\0' };

 

    // printing string

    int i = 0;

    while (arr[i]) {

        printf("%c", arr[i++]);

    }

    return 0;

}

2. Multidimensional Array in C

Multi-dimensional Arrays in C are those arrays that have more than one dimension. Some of the popular multidimensional arrays are 2D arrays and 3D arrays. We can declare arrays with more dimensions than 3d arrays but they are avoided as they get very complex and occupy a large amount of space.

A. Two-Dimensional Array in C

A Two-Dimensional array or 2D array in C is an array that has exactly two dimensions. They can be visualized in the form of rows and columns organized in a two-dimensional plane.

Syntax of 2D Array in C

datatype array_name[size1] [size2];

Here,

• size1: Size of the first dimension.
• size2: Size of the second dimension.

EXAMPLE

#include <stdio.h>

 

int main()

{

 

    // declaring and initializing 2d array

    int arr[2][3] = { 10, 20, 30, 40, 50, 60 };

 

  printf("2D Array:\n");

    // printing 2d array

    for (int i = 0; i < 2; i++) {

        for (int j = 0; j < 3; j++) {

            printf("%d ",arr[i][j]);

        }

        printf("\n");

    }

 

    return 0;

} 

Three-Dimensional Array in C

Another popular form of a multi-dimensional array is Three Dimensional Array or 3D Array. A 3D array has exactly three dimensions. It can be visualized as a collection of 2D arrays stacked on top of each other to create the third dimension.

Syntax of 3D Array in C

array_name [size1] [size2] [size3];

EXAMPLE

#include <stdio.h>

 

int main()

{

 

    // 3D array declaration

    int arr[2][2][2] = { 10, 20, 30, 40, 50, 60 };

 

    // printing elements

    for (int i = 0; i < 2; i++) {

        for (int j = 0; j < 2; j++) {

            for (int k = 0; k < 2; k++) {

                printf("%d ", arr[i][j][k]);

            }

            printf("\n");

        }

        printf("\n \n");

    }

    return 0;

}



STRINGS

C String Functions

There are many important string functions defined in "string.h" library.

No.	Function	Description
1)	strlen(string_name)	returns the length of string name.
2)	strcpy(destination, source)	copies the contents of source string to destination string.
3)	strcat(first_string, second_string)	concats or joins first string with second string. The result of the string is stored in first string.
4)	strcmp(first_string, second_string)	compares the first string with second string. If both strings are same, it returns 0.
5)	strrev(string)	returns reverse string.
6)	strlwr(string)	returns string characters in lowercase.
7)	strupr(string)	returns string characters in uppercase.