`luc092.c`¶

Problem Statement

Write a program to store names in a file. Display the n-th name in the list, where n is read from the keyboard.

Metadata¶

Property	Detail
Author	Amit Dutta amitdutta4255@gmail.com
Date	08 Feb 2026
License	MIT License (See the LICENSE file for details)
Difficulty	Intermediate (index: 4 / 10)

Concepts¶

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Pointers
Recursion
Array

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Source Code¶

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

void create_name_file();

int main()
{
    FILE *fp;
    char name[50];
    int n, current = 0, found = 0;

    create_name_file();

    printf("Enter value of n to find n-th name: ");
    scanf("%d", &n);

    fp = fopen("names.txt", "r");
    if (!fp) exit(1);

    // Assuming one name per line
    while (fgets(name, sizeof(name), fp) != NULL)
    {
        current++;
        if (current == n)
        {
            printf("The %d-th name is: %s", n, name);
            found = 1;
            break;
        }
    }

    if (!found)
        printf("Record not found (Only %d names exist).\n", current);

    fclose(fp);
    return 0;
}

void create_name_file()
{
    FILE *f = fopen("names.txt", "w");
    fprintf(f, "Alice\nBob\nCharlie\nDavid\nEve\nFrank\n");
    fclose(f);
}

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 (luc092.c):

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

    void create_name_file();

    int main()
    {
        FILE *fp;
        char name[50];
        int n, current = 0, found = 0;

        create_name_file();

        printf("Enter value of n to find n-th name: ");
        scanf("%d", &n);

        fp = fopen("names.txt", "r");
        if (!fp) exit(1);

        // Assuming one name per line
        while (fgets(name, sizeof(name), fp) != NULL)
        {
            current++;
            if (current == n)
            {
                printf("The %d-th name is: %s", n, name);
                found = 1;
                break;
            }
        }

        if (!found)
            printf("Record not found (Only %d names exist).\n", current);

        fclose(fp);
        return 0;
    }

    void create_name_file()
    {
        FILE *f = fopen("names.txt", "w");
        fprintf(f, "Alice\nBob\nCharlie\nDavid\nEve\nFrank\n");
        fclose(f);
    }

luc092.c¶