calculation problem!sometimes does wrong and absurb calculations

[cleontangy]

i'm just a beginner here..so forgive me if i make some mistakes ><!here's the problem,sometimes during compiling,i input a correct number but the sub total output gives a absurdly huge number and sometimes it just works normally,i don't know what is wrong here.i hope u guys can help n enlighten me!thanks!








#include <iostream>
#include <string>
#include <iomanip>
#include <fstream>
#include <windows.h>
using namespace std;

int main()
{
ofstream file;
file.open("grcr2.txt", ios::in|ios::out|ios::trunc);

if (!file.is_open())
{
cout<<"error while opening the file";

}

else
{

int z;
char ans, y,n;
const int num1=10000;
cout<<"Enter number of items: ";
cin>>z;
if(z<=0)
{
cout<<"invalid number of items.";
return 0;
}
string name[num1]={""};
string date[num1]={""};
double number[num1]={NULL},cost[num1]={NULL}, TC[num1]={NULL},cash,change1,TTC;
cin.ignore(1024,'\n');


for(int i=0;i<z;i++)
{
cout << "\nEnter name of ITEM "<< i+1 <<"(t to terminate): ";
getline(cin,name[i]);
if(name[i]=="t")
{
name[i]="";
break;
}
cout << "Enter date of purchase: ";
cin >> date[i];
cout << "Enter amount of item: " ;
cin >> number[i];
cout << "Enter the cost of item: ";
cin >> cost[i];
cin.ignore(1024,'\n');
TC[i]=number[i] * cost[i];

TTC += TC[i]; //this line is the calculation for sub total i dont know if this code will cause some glitches or not.



}
file << "\nItem" << std::setw(25) << " Date" << std::setw(15)
<< " Amount "<< std::setw(17) <<" Cost of item" <<std::setw(17)<< "Total cost\n";
file << std::setfill('-') << std::setw(80) << "-" << std::endl;
file << std::setfill(' ');
for (int i=0; i<z; i++)
{
file <<"ITEM"<< i+1 << ": ";
if(i+1==10)
{
file << std::setw(18) << std::left;
}
else
file << std::setw(19) << std::left;
file << name[i] << std::setw(12) << std::left;
file << date[i] <<"x"<< std::setw(11) << std::left;
file << fixed <<setprecision(0) << number[i] <<"$"<< std::setw (17) << std::left;
file << fixed << setprecision(2) <<cost[i]<<"$";
file <<TC[i]<<endl;
}
file << std::setfill('-') << std::setw(80) << "-" << std::endl;
file << std::setfill(' ');
cout <<fixed<< "sub total: $"<<setprecision(2)<<TTC<< endl;
file <<fixed<<"sub total : $"<<setprecision(2)<<TTC<<endl;
cout <<"payment details -- cash: $";
cin >> cash;
file <<fixed<<"payment details -- cash: $"<<setprecision(2)<<cash<<endl;

change1 = cash - TTC;

if(change1>= -0)
{
cout<<"change due: $"<<fixed<<setprecision(2)<<change1<<"\n" ;
file<<"change due: $"<<fixed<<setprecision(2)<<change1<<"\n" ;

}

else
{
cout<<" NOT ENOUGH CASH!"<<endl;
file<<" NOT ENOUGH CASH!"<<endl;
}



file.close();
cout<<"Do you want to open textfile?(input y or n): ";
cin>>ans;
if(ans=='y')
{
ShellExecute(NULL,"open","notepad.exe","grcr2.txt",NULL,SW_SHOWNORMAL);
system("PAUSE");
}
return 0;
}

}

[coder777]

gives a absurdly huge number and sometimes it just works normally

This is usually a sign for uninitialized variable. Indeed TTC is uninitialzed and hence this TTC += TC[i]; adds to a random number.

[cleontangy]

so i'll just have to double TTC = 0.00; will that solve the problem?

[coder777]

I'd suggest that you test it. Very likely.

[cleontangy]

thanks so much!!it is working fine now!i could'nt see the problem untill now xp