C program to delete a record from a file

Write a C program to delete a record from a file.

  #include <stdio.h>
  #include <string.h>
  #define MAX 256

  struct library {
        int id, bookCount;
        char name[MAX];
        float fine;
  };

  int main() {
        int id;
        FILE *fp1, *fp2;
        struct library ent;
        char filename[MAX], temp[] = "temp.txt";

        /* get the input file name from the user */
        printf("Enter your file name:");
        fgets(filename, MAX, stdin);
        filename[strlen(filename) - 1] = '\0';

        /* open the input file in read mode */
        fp1 = fopen(filename, "r");

        /* error handling */
        if (!fp1) {
                printf("Unable to open input file!!\n");
                return 0;
        }

        /* open temporary file in write mode */
        fp2 = fopen(temp, "w");

        /* error handling */
        if (!fp2) {
                printf("Unable to open temporary file!!\n");
                fclose(fp1);
                return 0;
        }

        /* print the records in the input file */
        printf("Records in input file:\n");
        while (!feof(fp1)) {
                fscanf(fp1, "%d %s %d %f\n", &ent.id, ent.name,
                                &ent.bookCount, &ent.fine);

                if (feof(fp1)) {
                        continue;
                }

                printf("Details of %s:\n", ent.name);
                printf("ID Number: %d\n", ent.id);
                printf("No of books taken: %d\n", ent.bookCount);
                printf("Fine amount: %.2f\n\n", ent.fine);
        }

        /* rewind file pointer of input file to start */
        rewind(fp1);

        /* get the record user wants to delete */
        printf("Enter the record you want to delete(ID no):");

        scanf("%d", &id);

        /* delete the given record */

        while (!feof(fp1)) {

                fscanf(fp1, "%d%s%d%f", &ent.id, ent.name,

                                &ent.bookCount, &ent.fine);

                if (feof(fp1)) {

                        continue;

                }

                if (id == ent.id)

                        continue;

                fprintf(fp2, "%d %s %d %f\n", ent.id, ent.name,

                                ent.bookCount, ent.fine);

        }

        /* close the opened files */

        fclose(fp1);

        fclose(fp2);

        /* remove the input file */

        remove(filename);

        /* rename the temporary file */

        rename(temp, filename);

        /* open the input file after delete operation */

        fp1 = fopen(filename, "r");

        /* error handling */

        if (!fp1) {

                printf("Unable to open the file %s\n", filename);

                return 0;

        }

        /* records in  input file after deletion operation */

        printf("\nRecords in input file after deletion operation:\n");

        while (!feof(fp1)) {

                fscanf(fp1, "%d %s %d %f\n", &ent.id, ent.name,

                                &ent.bookCount, &ent.fine);

                if (feof(fp1)) {

                          continue;

                }

                printf("Details of %s:\n", ent.name);

                printf("ID Number: %d\n", ent.id);

                printf("No of books taken: %d\n", ent.bookCount);

                printf("Fine amount: %.2f\n\n", ent.fine);

        }

        /* close the opened file */

        fclose(fp1);

        return 0;

  }

  Output:

  jp@jp-VirtualBox:~/$ ./a.out
  Enter your file name:library.txt
  Records in input file:
  Details of Samuel:
  ID Number: 1
  No of books taken: 4
  Fine amount: 100.74

  Details of Raja:
  ID Number: 2
  No of books taken: 3
  Fine amount: 150.11

  Details of Gopi:
  ID Number: 3
  No of books taken: 5
  Fine amount: 175.19

  Details of Sam:
  ID Number: 4
  No of books taken: 2
  Fine amount: 100.00

  Enter the record you want to delete(ID no):4

  Records in input file after deletion operation:
  Details of Samuel:
  ID Number: 1
  No of books taken: 4
  Fine amount: 100.74

  Details of Raja:
  ID Number: 2
  No of books taken: 3
  Fine amount: 150.11

  Details of Gopi:
  ID Number: 3
  No of books taken: 5
  Fine amount: 175.19

SEE ALSO

---

• c program to write a string into a file
• c program to read numbers from a file and write even, odd and prime numbers in separate files
• c program to create a file and store "hello world" in it
• c program to read the contents of the given file
• c program to delete all blank lines in a file
• c program to check whether a directory exists or not
• c program to check whether a file exists or not
• c program to copy a file from one location to another
• c program to create, read, edit and close a file
• c program to create a file with input content
• c program to read a file line by line
• c program to compare two files character by character
• c program to concatenate two files
• c program to convert lowercase characters in a file to uppercase
• c program to convert uppercase characters in a file to lowercase
• c program to list all files in a directory
• c program to list all files in a directory recursively
• c program to append data into a file
• c program to count number of lines in a file
• c program to delete a file or directory
• c program to print the source code of itself as output
• c program to convert the contents in a file from lowercase to uppercase and vice versa
• c program to merge two files
• c program to move a file to different location
• c program to replace articles with space in a text file
• c program to print the words in a file starting with the given character
• c program to delete given word in a file
• c program to replace a word in a file
• c program to merge alternate lines from two files
• c program to remove numbers in a file
• c program to check end of file
• c program to compare two files line by line
• c program to delete specific line from a file
• c program to replace specific line in a file
• c program to take input from a file
• c program to delete a record from a file
• c program to find the number of character, words and lines in a file
• c program to sort characters in each words of a file
• c program to convert text file to binary
• c program to split a file to multiple files
• c program to find the file type, permission, size and last modification date of the given file
• c program to encrypt and decrypt contents of a file
• c program to eliminate comments from a file