Program 66 - CSU1128 - CSE 2026 - Shoolini University

Program to demonstrate the file handling by saving the values entered by the user

Explanation

The program demonstrates file handling in C by saving the values entered by the user (name and age) to a file.

Header

The code begins with including the standard input-output header file and the string header file using #include <stdio.h> and #include <string.h>.

Variable Declaration

The main() function is defined, and variables are declared:

char name[100];: Array to hold the user's full name.
int age;: Variable to hold the user's age.

Program Description

The program prints a description message for the user to understand its functionality.

User Input

The user is prompted to enter their full name and age:

printf("Enter your full name: ");: Prompts the user to enter their full name.
fgets(name, sizeof(name), stdin);: Reads the full name including spaces and stores it in the array name.
printf("Enter your age: ");: Prompts the user to enter their age.
scanf("%d", &age);: Reads the age entered by the user and stores it in age.
name[strcspn(name, "\n")] = 0;: Removes the newline character from the end of the string name.

File Handling

The program demonstrates file handling by opening a file, writing data to it, and then closing it:

FILE *fp = fopen("data.txt", "a+");: Opens a file named data.txt for appending. If the file does not exist, it will be created.
fprintf(fp, "Name: %s\n", name);: Writes the user's name to the file.
fprintf(fp, "Age: %d\n", age);: Writes the user's age to the file.
fclose(fp);: Closes the file.

Output Result

The program prints a message indicating that the data has been written to the file:

printf("Data written to file data.txt");: Prints a message indicating successful writing of data to the file.

Program End

The program ends with return 0; to indicate successful execution.

Code

                    
/*
 * -----------------------------------------------------------
 * Logic Building with Computer Programming (CSU1128)
 * Instructor: Dr. Pankaj Vaidya | Author: Divya Mohan
 * 
 * This code is a part of the educational initiative by dmj.one
 * with aim of empowering and inspiring learners in the field of
 * Computer Science and Engineering through the respective courses.
 * 
 * (c) 2022, Divya Mohan for dmj.one. All rights reserved.
 * -----------------------------------------------------------
 */

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

int main()
{
    printf("\n\n Program to demonstrate the file handling by saving the values entered by the user. \n\n");

    char name[100];
    int age;

    printf("Enter your full name: ");
    fgets(name, sizeof(name), stdin); // Read the full name, including space

    printf("Enter your age: ");
    scanf("%d", &age);

    name[strcspn(name, "\n")] = 0; // remove the newline character from the end of the string

    // Open a file for writing
    FILE *fp = fopen("data.txt", "a+");

    // Write the input data to the file
    fprintf(fp, "Name: %s", name); // The name already includes a newline character
    fprintf(fp, "Age: %d\n", age);

    // Close the file
    fclose(fp);
   
    printf("Data written to file data.txt");
    return 0;
}

Output

Program to demonstrate the file handling by saving the values entered by the user.

Enter your full name: dmj.one Pvt. Ltd.
Enter your age: 11
Data written to file data.txt