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pc-ip-20.c

Problem Statement

Question 20: Write a C program that defines an array of integers, and includes a user-defined function named reverseArray with the signature void reverseArray(int arr[], int size);.

Metadata

Property Detail
Author Amit Dutta amitdutta4255@gmail.com
Date 05 Jan 2026
License MIT License (See the LICENSE file for details)
Difficulty Intermediate (index: 4 / 10)

Concepts

Beta Feature

This concept detection system is still in beta and may occasionally show incorrect or incomplete results.

  • Array
  • Pointers
  • Iteration
  • Sorting (possible)
  • Recursion

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Source Code

#include<stdio.h>
#include<stdlib.h>

void inputArray(int [], int);
void reverseArray(int [], int);
void printArray(int [], int);

int main() {
    int n, *arr = NULL;
    printf("How many element do you want enter: ");
    scanf("%d", &n);
    arr = (int *)malloc(n * sizeof(int));
    if(arr == NULL) {
        printf("\nMemory allocation failed.");
        return 1;
    }
    inputArray(arr, n);
    printf("\nBefore Reverse: ");
    printArray(arr, n);
    reverseArray(arr, n);
    printf("\nAfter reverse: ");
    printArray(arr, n);
    free(arr);
    return 0;
}

void inputArray(int arr[], int n) {
    int i;
    for(i = 0; i < n; i++) {
        printf("Enter element %d: ", i + 1);
        scanf("%d", &arr[i]);
    }
}

void printArray(int arr[], int n) {
    int i;
    printf("[");
    for(i = 0; i < n; i++) {
        printf("%d", arr[i]);
        if(i < n - 1) {
            printf(", ");
        }
    }
    printf("]");
}

void reverseArray(int arr[], int size) {
    int i = 0;
    int j = size - 1;
    int temp;
    while(i < j) {
        temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
        i++;
        j--;
    }
}

Explanation

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    You are explaining a C programming code to a beginner.

    STRICT RULES:

    - Only use the given code. Do NOT assume anything not present.

    - Do NOT add extra examples.

    - Keep explanation clear and short.

    - If something is unclear, say "Not clear from code".

    - Follow the exact format below. Do NOT change headings.

    FORMAT:

    [START]

    ## What it does

    (Explain the overall purpose in 1-2 sentences)

    ## Step-by-step

    (Explain how the code works in steps, simple language)

    ## Key Concepts

    (List concepts like loop, condition, function, etc.)

    ## Notes

    (Mention any limitations, errors, or assumptions)

    [END]

    CODE (pc-ip-20.c):

    #include<stdio.h>
    #include<stdlib.h>

    void inputArray(int [], int);
    void reverseArray(int [], int);
    void printArray(int [], int);

    int main() {
        int n, *arr = NULL;
        printf("How many element do you want enter: ");
        scanf("%d", &n);
        arr = (int *)malloc(n * sizeof(int));
        if(arr == NULL) {
            printf("\nMemory allocation failed.");
            return 1;
        }
        inputArray(arr, n);
        printf("\nBefore Reverse: ");
        printArray(arr, n);
        reverseArray(arr, n);
        printf("\nAfter reverse: ");
        printArray(arr, n);
        free(arr);
        return 0;
    }

    void inputArray(int arr[], int n) {
        int i;
        for(i = 0; i < n; i++) {
            printf("Enter element %d: ", i + 1);
            scanf("%d", &arr[i]);
        }
    }

    void printArray(int arr[], int n) {
        int i;
        printf("[");
        for(i = 0; i < n; i++) {
            printf("%d", arr[i]);
            if(i < n - 1) {
                printf(", ");
            }
        }
        printf("]");
    }

    void reverseArray(int arr[], int size) {
        int i = 0;
        int j = size - 1;
        int temp;
        while(i < j) {
            temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
            i++;
            j--;
        }
    }