Skip to content

What are Arrays Strings

Arrays

  1. Definition: An array is a data structure that stores a fixed-size, ordered collection of elements of the same data type. Each element in an array is identified by its index or position.

  2. Features:

    • Fixed Size: Arrays have a predetermined size when they are declared, and this size cannot be changed during runtime.
    • Homogeneous: All elements in an array must be of the same data type (e.g., integers, floats, characters).
    • Indexed: Elements in an array are accessed using an index, starting from 0 for the first element.
    • Contiguous Memory: Array elements are stored in contiguous memory locations.

  3. Examples:

    • Integer Array: int numbers[5];
    • Character Array (String): char greeting[10];

  4. Common Operations:

    • Accessing Elements: array[index]
    • Modifying Elements: array[index] = value
    • Iterating through Elements: Using loops (e.g., for loop)
    • Finding Length: sizeof(array) / sizeof(array[0])

Strings

  1. Definition: A string is a sequence of characters, represented as an array of characters. In many programming languages, strings are treated as a special type of array with built-in functions for text manipulation.

  2. Features:

    • Variable Length: Strings can vary in length, and their size can change during runtime.
    • Characters: Strings are composed of characters, typically represented using the char data type.
    • Null-Terminated: In C-style strings, a null character ('\0') marks the end of the string.

  3. Examples:

    • C-style String: char greeting[] = "Hello";
    • String in Python: "Hello, World"

  4. Common Operations:

    • Concatenation: Combining two or more strings (e.g., "Hello, " + "World")
    • Length: Finding the number of characters in a string (e.g., strlen in C/C++)
    • Comparison: Checking if two strings are equal (e.g., "abc" == "def")
    • Substring: Extracting a portion of a string (e.g., "Hello".substring(1, 3) in Java)

Array

Method-1

Array.cpp

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
#include<bits/stdc++.h>
using namespace std;

int main() {
    int a, b, c, d, e
    cin >> a >> b >> c >> d >> e;

    int sum = a + b + c + d + e;
    cout << sum;
    return 0;
}

Input: 1 2 3 4
Output: 10

Method-2

Array.cpp

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
#include<bits/stdc++.h>
using namespace std;

int main() {
    int arr[5];
    cin >> arr[0] >> arr[1] >> arr[2] >> arr[3] >> arr[4];

    int sum = arr[0] + arr[1] + arr[2] + arr[3] + arr[4];
    cout << sum;
    return 0;
}

Input: 1 2 3 4 5
Output: 15

2D Array

Method-1

Matrix.cpp

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
#include<bits/stdc++.h>
using namespace std;

int main() {
    int arr[2][2];
    cin >> arr[0][0] >> arr[0][1] >> arr[1][0] >> arr[1][1];

    int sum = arr[0][0] + arr[0][1] + arr[1][0] + arr[1][1];
    cout << sum;
    return 0;
}

Input: 1 2 3 4
Output: 10

String

Method-1

String.cpp

1
2
3
4
5
6
7
8
9
#include<bits/stdc++.h>
using namespace std;

int main() {
    string str = "Akash Singh";
    int len = str.size();
    cout << str[len-1];
    return 0;
}

Output: h