C Program to Maintain Employee Records using File Handling

Below is the source code for C Program to Maintain Employee Records using File Handling which is successfully compiled and run on Windows System to produce desired output as shown below :

SOURCE CODE : :

/*  C Program to Maintain Employee Records using File Handling  */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define size 200

struct emp
{
    int id;
    char *name;
}*emp1, *emp3;

void display();
void create();
void update();

char * arrr = "C:\\Users\\acer\\Documents\\file4.txt";

FILE *fp, *fp1;
int count = 0;

void main()
{
    int i, n, ch;

    printf("1] Create a Record\n");
    printf("2] Display Records\n");
    printf("3] Update Records\n");
    printf("4] Exit");
    while (1)
    {
        printf("\nEnter your choice : ");
        scanf("%d", &ch);
        switch (ch)
        {
        case 1:
            fp = fopen(arrr, "a");
            create();
            break;
        case 2:
            fp1 = fopen(arrr,"rb");
            display();
            break;
        case 3:
            fp1 = fopen(arrr, "r+");
            update();
            break;
        case 4:
            exit(0);
        }
    }
}

/* To create an employee record */
void create()
{
    int i;
    char *p;

    emp1 = (struct emp *)malloc(sizeof(struct emp));
    emp1->name = (char *)malloc((size)*(sizeof(char)));
    printf("Enter name of employee : ");
    scanf(" %[^\n]s", emp1->name);
    printf("Enter emp id : ");
    scanf(" %d", &emp1->id);
    fwrite(&emp1->id, sizeof(emp1->id), 1, fp);
    fwrite(emp1->name, size, 1, fp);
    count++;   // count to number of entries of records
    fclose(fp);
}

/* Display the records in the file */
void display()
{
    emp3=(struct emp *)malloc(1*sizeof(struct emp));
    emp3->name=(char *)malloc(size*sizeof(char));
    int i = 1;

    if (fp1 == NULL)
        printf("\nFile not opened for reading");
    while (i <= count)
    {
        fread(&emp3->id, sizeof(emp3->id), 1, fp1);
        fread(emp3->name, size, 1, fp1);
        printf("\n%d %s",emp3->id,emp3->name);
        i++;
    }
    fclose(fp1);
    free(emp3->name);
    free(emp3);
}

void update()
{
    int id, flag = 0, i = 1;
    char s[size];

    if (fp1 == NULL)
    {
        printf("File cant be opened");
        return;
    }
    printf("Enter employee id to update : ");
    scanf("%d", &id);
    emp3 = (struct emp *)malloc(1*sizeof(struct emp));
        emp3->name=(char *)malloc(size*sizeof(char));
    while(i<=count)
    {
        fread(&emp3->id, sizeof(emp3->id), 1, fp1);
        fread(emp3->name,size,1,fp1);
        if (id == emp3->id)
        {
            printf("Enter new name of emplyee to update : ");
            scanf(" %[^\n]s", s);
            fseek(fp1, -204L, SEEK_CUR);
            fwrite(&emp3->id, sizeof(emp3->id), 1, fp1);
            fwrite(s, size, 1, fp1);
            flag = 1;
            break;
        }
        i++;
    }
    if (flag != 1)
    {
        printf("No employee record found");
        flag = 0;
    }
    fclose(fp1);
    free(emp3->name);        /* to free allocated memory */
    free(emp3);
}

OUTPUT : :

1] Create a Record
2] Display Records
3] Update Records
4] Exit
Enter your choice : 1
Enter name of employee : codezclub
Enter emp id : 1

Enter your choice : 1
Enter name of employee : Max
Enter emp id : 2

Enter your choice : 1
Enter name of employee : John
Enter emp id : 3

Enter your choice : 2

1 codezclub
2 Max
3 John
Enter your choice : 3
Enter employee id to update : 2
Enter new name of emplyee to update : Max Payne

Enter your choice : 2

1 codezclub
2 Max Payne
3 John
Enter your choice : 4

Process returned 0

Above is the source code for C Program to Maintain Employee Records using File Handling which is successfully compiled and run on Windows System.The Output of the program is shown above .