C File updating and creating help -
i have 2 .dat(ascii) files. both sorted.
1: clients file containing ; account number , name ,balance 2: transaction file containing; account number ,date,saleamount(transaction amount)
what trying accomplish create new updated clients file has updated balances clients based on adding or subtracting saleamount of matching transaction.
my code far enables me :
1: if there not more 1 transactions client code runs writes .dat file clients , updated balances.
2:if there more 1 transactions client code run print screen updated clients , accounts eg:
1 james 540.00 2 john 762.00 3 paul 414.00 4 sam 502.00
will displayed , there 2 transactions john created .dat file while contain
1 james 540.00 2 john 662.00 2 john 762.00 3 paul 414.00 4 sam 502.00
my problem lies here, need find way of having created .dat contain 1 line each client ( account number)
my code attached appreciated.
#include <stdio.h> #include <string.h> int main(void) { int account, matches=0; /* account number */ char date[ 30 ]; /* account date */ double balance, saleamount,total=0, temp;; /* account saleamount */ int transaccount; char name [ 30 ]; char lastname[30]; int lastaccount=-1; double lastbalance; file *cfptr; /* cfptr = clients.dat file pointer */ file *ctptr; /* cfptr = transaction.dat file pointer */ file *cfptr2; /* cfptr2 = new client file */ cfptr2 = fopen( "clientupdate.dat", "w" ); /* fopen opens file; exits program if file cannot opened */ if ( ( cfptr = fopen( "clients.dat", "r" ) ) == null ) { printf( "clients not opened\n" ); /*fflush(stdin);*/ } /* end if */ else if( ( ctptr = fopen( "transactions.dat", "r" ) ) == null) { printf( "file not opened\n" ); /*fflush(stdin);*/ } else { /* read account, date,name, balance , saleamount files */ fscanf( cfptr, "%d%s%lf", &account, &name, &balance ); /*fflush(stdin);*/ fscanf( ctptr, "%d%s%lf", &transaccount, &date, &saleamount ); /*fflush(stdin);*/ printf( "%-13s%-10s%s\n", " account", "name", "balance" ); printf("|----------------------------------|\n"); while( !feof(ctptr)) { while( !feof(cfptr) &&matches==0 ) { if(account == transaccount) { if (lastaccount != account) { if (lastaccount != -1) printf(" %-10d%-10s%.2lf\n", lastaccount, lastname, lastbalance); lastaccount = account; strcpy (lastname, name); } matches=1; total=0; temp = balance+saleamount; total = total + temp; balance = total; lastbalance = balance; } else { fscanf( cfptr, "%d%s%lf", &account, &name, &balance ); /*fflush(stdin);*/ } } fprintf( cfptr2, "%d %s %.2lf\n", account, name, total ); fscanf( ctptr, "%d%s%lf", &transaccount, &date, &saleamount ); /*fflush(stdin);*/ matches=0; } } if (lastaccount != -1) printf(" %-10d%-10s%.2lf\n", lastaccount, lastname, lastbalance); fclose( cfptr2 ); getchar(); return 0; }
as promised, here quick exmaple of father-son update. have not bothered checking file opening errors have them in code, , real application need check more eof fscanf in order detect invalid file formatting.
#include <stdlib.h> #include <stdio.h> #define bool int #define false 0 #define true !false #define max_account_number 99999 typedef struct { int accountnumber; char accountname[30]; float accounttotal; } clientrecordtype; typedef struct { int accountnumber; char transactiondate[30]; float transactionamount; } transactionrecordtype; file *oldclientfile; file *newclientfile; file *transactionfile; void getnextclient(file *p_clientfile, clientrecordtype *p_clientrecord) { if (eof == fscanf(p_clientfile, "%d%s%f", &p_clientrecord->accountnumber, &p_clientrecord->accountname, &p_clientrecord->accounttotal)) p_clientrecord->accountnumber = max_account_number; } void getnexttransaction(file *p_transactionfile, transactionrecordtype *p_transactionrecord) { if (eof == fscanf(p_transactionfile, "%d%s%f", &p_transactionrecord->accountnumber, &p_transactionrecord->transactiondate, &p_transactionrecord->transactionamount)) p_transactionrecord->accountnumber = max_account_number; } void writeupdatedclientrecord(file *p_newclientfile, clientrecordtype *p_clientrecord) { fprintf(p_newclientfile, "%d %s %.2f ", p_clientrecord->accountnumber, p_clientrecord->accountname, p_clientrecord->accounttotal); } bool performtransactionupdate(file *p_oldclientfile, file *p_newclientfile, file *p_transactionfile) { clientrecordtype clientrecord; transactionrecordtype transactionrecord; getnextclient(p_oldclientfile, &clientrecord); getnexttransaction(p_transactionfile, &transactionrecord); while (max_account_number != clientrecord.accountnumber) { if (clientrecord.accountnumber == transactionrecord.accountnumber) { clientrecord.accounttotal += transactionrecord.transactionamount; getnexttransaction(p_transactionfile, &transactionrecord); } else if (clientrecord.accountnumber < transactionrecord.accountnumber) { writeupdatedclientrecord(p_newclientfile, &clientrecord); getnextclient(p_oldclientfile, &clientrecord); } else { return false; } } if (max_account_number != transactionrecord.accountnumber) return false; return true; } int main(int argc, char *argv[]) { oldclientfile = fopen("clients.dat", "r"); newclientfile = fopen("newclients.dat", "w"); transactionfile = fopen("transactions.dat", "r"); if (performtransactionupdate(oldclientfile, newclientfile, transactionfile)) printf("\nupdate completed without errors!\n"); else printf("\nunsorted files or invalid transactions encountered\n"); close(newclientfile); close(oldclientfile); close(transactionfile); return 0; } 
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