Customer Billing System Project Abstract:

User Defined Functions Used:

Although graphics has not been used in this project, the application of user defined functions and structures have been effectively used here. The major user defined functions used in this C project are:

• void input()
• void writefile()
• void search()
• void output()

The function void input() is used to add the new customer account i.e. with the help of this functions the parameters such as name, address, phone number, amount paid etc. are asked and entered. Another function void writefile() has been utilized to create a file on hard disc of computer for storing the information and data of a customer.

The function void search() has been used to look for previously stored accounts either by name or by number of the customer. The fourth and the last user defined function used in this Customer Billing System Project in C is void output() which has been defined to show the result as console output.

In Customer Billing System, structure has very beautifully used to group the data type in single unit. The date variables (day, month and year) have been grouped in the structures named date where as other variables such as name, number, street, paid amount etc. are grouped under another structure named account.

Customer Billing System application is so simple to use. In order to use the application, click at the exe file and then, you will have three options to:

1. To add account
2. To search account
3. To exit

As per your need, enter 1, 2,or 3 and follow the instructions provided by the application itself.

Features:

1. It can hold any number of accounts and account can be added to the program at any time.
2. The programming of simple calculations such as calculation of due amount, balance etc. have been embed in the code of project.
3. The Customer Billing System project in C gives you the facility of searching the account by two ways, either by name of the customer or by the number of customer.
4. The due amount to be paid is shown as negative balance.
5. If you have nothing to do with the program, you can directly exit from the main menu.

CODE:

 #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;

  }