Arrays in C

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Arrays in C (1D & 2D Arrays)

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Introduction

In C programming, an array is used to store multiple values of the same data type in a single variable.

👉 Instead of creating many variables, we can use an array to store all values together.

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What is an Array?

An array is:
👉 A collection of elements of the same data type stored in contiguous memory locations

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Why Use Arrays?

• ✔ Store multiple values easily
• ✔ Reduce number of variables
• ✔ Easy data handling
• ✔ Efficient memory usage

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1. One-Dimensional Array (1D Array)

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Syntax

data_type array_name[size];

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Example

#include <stdio.h>

int main() {
    int arr[5] = {10, 20, 30, 40, 50};

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

    return 0;
}

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Output

10 20 30 40 50

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Accessing Elements

👉 Array elements are accessed using index:

arr[0], arr[1], arr[2]

👉 Index starts from 0

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Taking Input in Array

#include <stdio.h>

int main() {
    int arr[3], i;

    for (i = 0; i < 3; i++) {
        scanf("%d", &arr[i]);
    }

    for (i = 0; i < 3; i++) {
        printf("%d ", arr[i]);
    }

    return 0;
}

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Sample Output

Input: 1 2 3
Output: 1 2 3

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2. Two-Dimensional Array (2D Array)

👉 Used to represent tables or matrices

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Syntax

data_type array_name[rows][columns];

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Example

#include <stdio.h>

int main() {
    int arr[2][2] = {
        {1, 2},
        {3, 4}
    };

    int i, j;

    for (i = 0; i < 2; i++) {
        for (j = 0; j < 2; j++) {
            printf("%d ", arr[i][j]);
        }
        printf("\n");
    }

    return 0;
}

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Output

1 2
3 4

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Memory Representation

👉 1D Array:

[10][20][30][40][50]

👉 2D Array:

[1][2]
[3][4]

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Comparison Table

Feature	1D Array	2D Array
Structure	Single row	Rows & Columns
Index	One index	Two indices
Use	List	Matrix/Table

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Common Mistakes

• ❌ Accessing invalid index
• ❌ Not initializing array
• ❌ Wrong loop limits
• ❌ Confusing row & column

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Pro Tips

• ✔ Always start index from 0
• ✔ Use loops for arrays
• ✔ Practice 2D arrays
• ✔ Understand memory structure

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Conclusion

Arrays are essential in C programming. They allow storing and processing multiple values efficiently.

Master arrays to handle data effectively in programs.

👉 This article is part of Dharani Tech Edu Hub — where learning programming is made simple and practical.