Arrays

What is array?

Array is a collection of similar datatypes. We store multiple values in single variable.

Syntax :

datatype arrayname[size]

Example :

int marks[6];

Example :

#include <stdio.h>

int main() {

    int rolls[5];

    rolls[0] = 10;
    rolls[1] = 15;
    rolls[2] = 30;
    rolls[3] = 8;
    rolls[4] = 20;

    printf("\n%d", rolls[0]);
    printf("\n%d", rolls[1]);
    printf("\n%d", rolls[2]);
    printf("\n%d", rolls[3]);
    printf("\n%d", rolls[4]);

    return 0;

}

⚙️ Output :

10
15
30
8
20

Example :

#include <stdio.h>

int main() {

    int rolls[5] = {5, 10, 15, 20, 25}

    printf("\n%d", rolls[0]);
    printf("\n%d", rolls[1]);
    printf("\n%d", rolls[2]);
    printf("\n%d", rolls[3]);
    printf("\n%d", rolls[4]);

    return 0;

}

⚙️ Output :

5
10
15
20
25

Example :

#include <stdio.h>

int main() {
    int rolls[5] = {5, 10, 15, 20, 25};

    for(int i=0; i<5; i++)
    {
        printf("\n%d", rolls[i]);
    }
    return 0;
}

⚙️ Output :

5
10
15
20
25

Reverse an Array

Example 1 : Print an array in reverse format.

#include <stdio.h>

int main() {

    int arr[6] = {18, 2, 17, 19, 21, 45};

    for(int i=5; i>=0; i--)
    {
        printf("%d, ", arr[i]);
    }

    return 0;
}

⚙️ Output :

45, 21, 19, 17, 2, 18,

Example 2 :

#include <stdio.h>

int main() {

    int arr[6] = {18, 2, 17, 19, 21, 45};

      printf("\n Before Reverse: ");
    for(int i=0; i<6; i++)
    {
        printf("%d, ",arr[i]);
    }

    int start=0;
    int end=5;

    while(start<end)
    {
        int temp = arr[start];
        arr[start] = arr[end];
        arr[end] = temp;

        start++;
        end--;
    }
    printf("\n After Reverse: ");
    for(int i=0; i<6; i++)
    {
        printf("%d, ",arr[i]);
    }

    return 0;
}

⚙️ Output :

Before Reverse: 18, 2, 17, 19, 21, 45,
After Reverse: 45, 21, 19, 17, 2, 18,