Here is a simple telephone billing system that I wrote in C programming language that performs basic database operation CRUD (Create, Retrieve, Update and Delete) through a text file. The code will work in Dev C++ compiler that is free to download over the Internet.
I am currently accepting programming work, IT projects, school and application development, programming projects, thesis and capstone projects, IT consulting work, computer tutorials, and web development work kindly contact me in the following email address for further details. If you want to advertise on my website kindly contact me also in my email address also. Thank you.
My email address is the following jakerpomperada@gmail.com, jakerpomperada@aol.com, and jakerpomperada@yahoo.com.
My mobile number here in the Philippines is 09173084360.
My telephone number at home here in Bacolod City, Negros Occidental Philippines is +63 (034) 4335675.
Here in Bacolod I also accepting computer repair, networking and Arduino Project development at a very affordable price.
My personal website is http://www.jakerpomperada.com
Sample Program Output
Program Listing
telephone.c
/* Jake R. Pomperada */
/* July 1, 2019 */
#include<stdio.h>
#include<conio.h>
#include<ctype.h>
#include<windows.h>
#include<stdlib.h>
struct subscriber
{
char phonenumber[20];
char name[50];
float amount;
}s;
void addrecords();
void listrecords();
void modifyrecords();
void deleterecords();
void searchrecords();
void payment();
char get;
int main()
{
int phonenumber;
char choice;
while (1)
{
system("cls");
printf("\n **********************************************");
printf("\n **** TELEPHONE BILLING MANAGEMENT SYSTEM ****");
printf("\n ***********************************************");
printf("\n");
printf("\n\t A : Adding new records.\n \t L : Listing of records");
printf("\n\t M : Modifying records.\n \t P : Payments");
printf("\n\t S : Searching records.");
printf("\n\t D : Deleting records.\n\t E : Exit Program\n");
printf("\n");
printf("\n\t PLEASE SELECT THE LETTERS ONLY " );
choice=getche();
choice=toupper(choice);
switch(choice)
{
case 'P':
payment();break;
case 'A' :
addrecords();break;
case 'L' :
listrecords();break;
case 'M':
modifyrecords();break;
case 'S' :
searchrecords();break;
case 'D':
deleterecords();break;
case 'E':
system("cls");
printf("\n\n\t\t\t\tTHANK YOU");
printf("\n\n\n\n\n:\n\tFOR USING OUR SERVICE");
Sleep(2000);
exit(0);
break;
default:
system("cls");
printf("Incorrect Input");
printf("\nAny key to continue");
getch();
}
}
}
void addrecords()
{
FILE *f;
char test;
f=fopen("data.dat","ab+");
if(f==0)
{ f=fopen("data.dat","wb+");
system("cls");
printf("please wait while we configure your computer");
printf("/npress any key to continue");
getch();
}
while(1)
{
system("cls");
printf("\n Enter phone number:");
scanf("%s",&s.phonenumber);
printf("\n Enter name:");
fflush(stdin);
scanf("%[^\n]",&s.name);
printf("\n Enter amount:");
scanf("%f",&s.amount);
fwrite(&s,sizeof(s),1,f);
fflush(stdin);
system("cls");
printf("1 record successfully added");
printf("\n Press esc key to exit, any other key to add other record:");
test=getche();
if(test==27)
break;
}
fclose(f);
}
void listrecords()
{
FILE *f;
int i;
if((f=fopen("data.dat","rb"))==NULL)
exit(0);
system("cls");
printf("Phone Number\t\tUser Name\t\t\tAmount\n");
for(i=0;i<79;i++)
printf("-");
while(fread(&s,sizeof(s),1,f)==1)
{
printf("\n%-10s\t\t%-20s\t\t $. %.2f /-",s.phonenumber,s.name,s.amount);
}
printf("\n");
for(i=0;i<79;i++)
printf("-");
fclose(f);
getch();
}
void deleterecords()
{
FILE *f,*t;
int i=1;
char phonenumber[20];
if((t=fopen("temp.dat","w+"))==NULL)
exit(0);
if((f=fopen("data.dat","rb"))==NULL)
exit(0);
system("cls");
printf("Enter the phone number to be deleted from the Database");
fflush(stdin);
scanf("%[^\n]",phonenumber);
while(fread(&s,sizeof(s),1,f)==1)
{
if(strcmp(s.phonenumber,phonenumber)==0)
{ i=0;
continue;
}
else
fwrite(&s,sizeof(s),1,t);
}
if(i==1)
{ system("cls");
printf("Phone number \"%s\" not found",phonenumber);
remove("data.dat");
rename("temp.dat","data.dat");
getch();
fclose(f);
fclose(t);
main();
}
remove("data.dat");
rename("temp.dat","file.dat");
system("cls");
printf("The Number %s Successfully Deleted!!!!",phonenumber);
fclose(f);
fclose(t);
getch();
}
void searchrecords()
{
FILE *f;
char phonenumber[20];
int flag=1;
f=fopen("data.dat","rb+");
if(f==0)
exit(0);
fflush(stdin);
system("cls");
printf("Enter Phone Number to search in our database");
scanf("%s", phonenumber);
while(fread(&s,sizeof(s),1,f)==1)
{
if(strcmp(s.phonenumber,phonenumber)==0)
{ system("cls");
printf(" Record Found ");
printf("\n\nPhonenumber: %s\nName: %s\nAmount: $ %0.2f\n",s.phonenumber,s.name,s.amount);
flag=0;
break;
}
else if(flag==1)
{ system("cls");
printf("Requested Phone Number Not found in our database");
}
}
getch();
fclose(f);
}
void modifyrecords()
{
FILE *f;
char phonenumber[20];
long int size=sizeof(s);
if((f=fopen("data.dat","rb+"))==NULL)
exit(0);
system("cls");
printf("Enter phone number of the subscriber to modify:");
scanf("%[^\n]",phonenumber);
fflush(stdin);
while(fread(&s,sizeof(s),1,f)==1)
{
if(strcmp(s.phonenumber,phonenumber)==0)
{
system("cls");
printf("\n Enter phone number:");
scanf("%s",&s.phonenumber);
printf("\n Enter name: ");
fflush(stdin);
scanf("%[^\n]",&s.name);
printf("\n Enter amount: ");
scanf("%f",&s.amount);
fseek(f,-size,SEEK_CUR);
fwrite(&s,sizeof(s),1,f);
break;
}
}
fclose(f);
}
void payment()
{
FILE *f;
char phonenumber[20];
long int size=sizeof(s);
float amt;
int i;
if((f=fopen("data.dat","rb+"))==NULL)
exit(0);
system("cls");
printf("Enter phone number of the subscriber for payment");
scanf("%[^\n]",phonenumber);
fflush(stdin);
while(fread(&s,sizeof(s),1,f)==1)
{
if(strcmp(s.phonenumber,phonenumber)==0)
{
system("cls");
printf("\n Phone No.: %s",s.phonenumber);
printf("\n Name: %s",s.name);
printf("\n Current amount: %f",s.amount);
printf("\n");
for(i=0;i<79;i++)
printf("-");
printf("\n\nEnter amount of payment :");
fflush(stdin);
scanf(" %f",&amt);
s.amount=(amt-s.amount);
fseek(f,-size,SEEK_CUR);
fwrite(&s,sizeof(s),1,f);
break;
}
}
system("cls");
printf("THANK YOU %s FOR YOUR TIMELY PAYMENTS",s.name);
getch();
fclose(f);
}
