Customer Billing System Project Using C Language
Introduction
Customer Billing System Project is a basic console application created to show the actual use of the C programming language and its capabilities as well as to develop an application that can be used to charge customers in any department store, shop, café, etc.
You may use this program to keep track of your frequent customers' information such as name, address, phone number, paid amount, due amount, payment date, and so on. You may also add and update accounts at any moment if you have a new client.
The Customer Billing System Project in C source code was created entirely in the C programming language, with no graphics.
Source Code for Customer Billing System Project Using C Language
#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
void input();
void writefile();
void search();
void output();
struct date{
int month;
int day;
int year;
};
struct account {
int number;
char name[100];
int acct_no;
float mobile_no;
char street[100];
char city[100];
char acct_type;
float oldbalance;
float newbalance;
float payment;
struct date lastpayment;
}customer;
int tl,sl,ts;
void main()
{
int i,n;
char ch;
clrscr();
_setcursortype(_NOCURSOR);
printf(" CUSTOMER BILLING SYSTEM:\n\n");
printf("===============================\n");
printf("\n1: to add account on list\n");
printf("2: to search customer account\n");
printf("3: exit\n");
printf("\n================================\n");
do{
printf("\nselect what do you want to do?");
ch=getche();
}while(ch<='0' || ch>'3');
switch(ch){
case '1':
clrscr();
printf("\nhow many customer accounts?");
scanf("%d",&n);
for(i=0;i<n;i++){
input();
if(customer.payment>0)
customer.acct_type=(customer.payment<0.1*customer.oldbalance)? 'O': 'D';
else
customer.acct_type=(customer.oldbalance>0)?'D' : 'C';
customer.newbalance=customer.oldbalance - customer.payment;
writefile();
}
main();
case '2':
clrscr();
printf("search by what?\n");
printf("\n1 --- search by customer number\n");
printf("2 --- search by customer name\n");
search();
ch=getche();
main();
case '3':
clrscr();
delay(700);
textcolor(RED);
gotoxy(25,25);
cprintf("\nA PROJECT BY BIDUR & SUJAN");
delay(1500);
exit(1);
}
}
void input()
{
FILE *fp=fopen("bidur.dat","rb");
fseek (fp,0,SEEK_END);
tl=ftell(fp);
sl=sizeof(customer);
ts=tl/sl;
fseek(fp,(ts-1)*sl,SEEK_SET);
fread(&customer,sizeof(customer),1,fp);
printf("\ncustomer no:%d\n",++customer.number);
fclose(fp);
printf(" Account number:");
scanf("%d",&customer.acct_no);
printf("\n Name:");
scanf("%s",customer.name);
printf("\n mobile no:");
scanf("%f",&customer.mobile_no);
printf(" Street:");
scanf("%s",customer.street);
printf(" City:");
scanf("%s",customer.city);
printf(" Previous balance:");
scanf("%f",&customer.oldbalance);
printf(" Current payment:");
scanf("%f",&customer.payment);
printf(" Payment date(mm/dd/yyyy):");
scanf("%d/%d/%d",&customer.lastpayment.month,&customer.lastpayment.day,&customer.lastpayment.year);
return;
}
void writefile()
{
FILE *fp;
fp=fopen("bidur.dat","ab");
fwrite(&customer,sizeof(customer),1,fp);
fclose(fp);
return;
}
void search()
{
char ch;
char nam[100];
int n,i,m=1;
FILE *fp;
fp=fopen("bidur.dat","rb");
do{
printf("\nenter your choice:");
ch=getche();
}while(ch!='1' && ch!='2');
switch(ch){
case '1':
fseek(fp,0,SEEK_END);
tl=ftell(fp);
sl=sizeof(customer);
ts=tl/sl;
do{
printf("\nchoose customer number:");
scanf("%d",&n);
if(n<=0 || n>ts)
printf("\nenter correct\n");
else{
fseek(fp,(n-1)*sl,SEEK_SET);
fread(&customer,sl,1,fp);
output();
}
printf("\n\nagain?(y/n)");
ch=getche();
}while(ch=='y');
fclose(fp);
break;
case '2':
fseek(fp,0,SEEK_END);
tl=ftell(fp);
sl=sizeof(customer);
ts=tl/sl;
fseek(fp,(ts-1)*sl,SEEK_SET);
fread(&customer,sizeof(customer),1,fp);
n=customer.number;
do{
printf("\nenter the name:");
scanf("%s",nam);
fseek(fp,0,SEEK_SET);
for(i=1;i<=n;i++)
{
fread(&customer,sizeof(customer),1,fp);
if(strcmp(customer.name,nam)==0)
{
output();
m=0;
break;
}
}
if(m!=0)
printf("\n\ndoesn't exist\n");
printf("\nanother?(y/n)");
ch=getche();
}while(ch=='y');
fclose(fp);
}
return;
}
void output()
{
printf("\n\n Customer no :%d\n",customer.number);
printf(" Name :%s\n",customer.name);
printf(" Mobile no :%.f\n",customer.mobile_no);
printf(" Account number :%d\n",customer.acct_no);
printf(" Street :%s\n",customer.street);
printf(" City :%s\n",customer.city);
printf(" Old balance :%.2f\n",customer.oldbalance);
printf(" Current payment:%.2f\n",customer.payment);
printf(" New balance :%.2f\n",customer.newbalance);
printf(" Payment date :%d/%d/%d\n\n",customer.lastpayment.month,customer.lastpayment.day,customer.lastpayment.year);
printf(" Account status :");
textcolor(128+RED);
switch(customer.acct_type)
{
case 'C':
cprintf("CURRENT\n\n");
break;
case 'O':
cprintf("OVERDUE\n\n");
break;
case 'D':
cprintf("DELINQUENT\n\n");
break;
default:
cprintf("ERROR\\n\n");
}
textcolor(WHITE);
return;
}
Output
Explanation
User-Defined Functions (UDFs) are used:
Although no images were utilized in this project, the utilization of user-defined functions and structures was quite beneficial. The following are the main user defined functions utilized in this C project:
- void input()
- void writefile()
- void search()
- void output()
The method void input() is used to create a new customer account, which means that it asks for and enters information such as name, address, phone number, and amount paid. Another method, void writefile(), was used to create a file on the computer's hard disk for keeping a customer's information and data.
The method void search() was used to seek for previously saved accounts using the customer's name or number. The fourth and final user defined function in this Customer Billing System Project in C is void output(), which is used to display the result on the console.
Structure has been utilized extremely well in the Customer Billing System to organize the data types into a single unit. Date variables (day, month, and year) are grouped in the date structure, whilst other variables (name, number, street, payment amount, and so on) are organized in the account structure.
The Customer Billing System application is very user-friendly. To use the program, double-click the exe file, and then choose one of three options:
- To add an account, click here.
- To find an account, click here.
- To leave
Enter 1, 2, or 3 depending on your needs, and then follow the application's instructions.
Features
- It can host an unlimited number of accounts, and new accounts may be added at any moment.
- Simple calculations, such as the computation of due amount, balance, and so on, have been programmed into the project code.
- The Customer Billing System project in C allows you to search for an account using one of two methods: the customer's name or the customer's number.
- The amount that has to be paid is shown as a negative balance.
- You may quit the software immediately from the main menu if you don't need it.
Final Words
The project may be utilized in a variety of ways. For starters, the created application file can be used. Second, the C source code for the Customer Billing System project may be used to learn about C programming and its many features, such as user defined functions, structures, and so on. It is strongly discouraged to submit this C project as your college/school C project without making any changes.
