循环读取数据文件不正确

Question

Goodday,

I have a loop reading a dat file but the loop reads the data incorrectly. My dat file contains the following data

46780976 3750.40
W 250.00
D 1200.00
W 75.00
W 375.00
D 1200.00
I 5.50
W 400.00
W 600.00
D 450.50
W 35.65

The output should be

Account number: 46780976
Opening balance: R3750.40

Transaction    Amount    Balance Bank costs
Withdrawal     250.00    4000.00
Deposit       1200.00Ct  2800.00
Withdrawal        75.00  2725.00
Withdrawal      1375.00   1350.00
Deposit        1200.00Ct 1550.00
Interest         5.50    1555.50
Withdrawal      400.00   1155.50
Withdrawal      600.00   555.50     25.00
Deposit         450.00Ct 1005.50
Withdrawal       35.65    969.85
Banking costs    25.00    969.60

Closing balance: R969.60

I get the following

Account number : 46780976

Opening Balance : R 3750.4

Transaction        Amount          Balance         Bank Costs


Withdrawal            250            3500.4
Deposit            0 Ct            3500.4
Interest              0            3500.4

Withdrawal            250            3225.4
Deposit            1200 Ct            4425.4
Interest              0            4425.4

Withdrawal            75            4325.4
Deposit            1200 Ct            5525.4
Interest              0            5525.4

Withdrawal            375            5125.4
Deposit            1200 Ct            6325.4
Interest              0            6325.4

Withdrawal            375            5925.4
Deposit            1200 Ct            7125.4
Interest              0            7125.4

Withdrawal            375            6725.4
Deposit            1200 Ct            7925.4
Interest              5.5            7930.9

Withdrawal            400            7505.9
Deposit            1200 Ct            8705.9
Interest              5.5            8711.4

Withdrawal            600            8086.4
Deposit            1200 Ct            9286.4
Interest              5.5            9291.9

Withdrawal            600            8666.9
Deposit            450.5 Ct            9117.4
Interest              5.5            9122.9

Withdrawal            35.65            9062.25
Deposit            450.5 Ct            9512.75
Interest              5.5            9518.25

Withdrawal            35.65            9457.6
Deposit            450.5 Ct            9908.1
Interest              5.5            9913.6
Bank Costs           25            9888.6            25


Closing Balance : R 9888.6
Press any key to continue . . .

My code :

do { 
   in_stream >> letter;

if (letter == 'W')

    in_stream >> withdrawal;
    openBalance -= withdrawal;
    cout << "\nWithdrawal" << "            "<< withdrawal << "            " << openBalance << endl;
    out_stream << withdrawal;

if (letter == 'D')

    in_stream >> deposit;
    openBalance += deposit;
    cout << "Deposit" <<"            "<< deposit <<" Ct" <<"            " << openBalance << endl;
    out_stream << deposit;


if (letter == 'I')

    in_stream >> interest;
    openBalance += interest;
    cout << "Interest" <<"              "<< interest <<"            " << openBalance << endl;
    out_stream << interest;

 if (openBalance < 1000)
     cout << "Bank Costs" <<"           "<< bankCost <<"            " << openBalance <<"            " << bankCost << endl;
    openBalance -= bankCost;
    out_stream << bankCost;

} while(!in_stream.eof());

Please point me in the right direction

thanks

Answer 1

Your first problem si with your if blocks. In C++, the 'if' statement affects the immeidately following thing - line of code or block.so...

if( Xxx )
    thisHappensOnlyIfXxxIsTrue
thisAlwaysHappens

if( Xxx )
    thisHappensOnlyIfXxxIsTrue
    thisAlwaysHappens  // even though it's indented


if( Xxx ) {
    thisHappensOnlyIfXxxIsTrue
    thisDependsOnXxxToo
}
thisAlwaysHappens

The next problem is that you're not clearing your variables every time the loop restarts. You need to insert a

do {
   deposit = 0;
   interest = 0;
   withdrawal = 0;

at the beginning (or end) of your loop, to ensure that you're not re-using the value from teh last loop iteration.

Answer 2

As the first line is:

46780976 3750.40

This line will pass but without what was intended:

in_stream >> letter;

Assuming of course that letter is of type char

EDIT

// You need to read in the initial values here

do { 
   in_stream >> letter;

if (letter == 'W')
{
    in_stream >> withdrawal;
    openBalance -= withdrawal;
    cout << "\nWithdrawal" << "            "<< withdrawal << "            " << openBalance << endl;
    out_stream << withdrawal;
}

if (letter == 'D')
{
    in_stream >> deposit;
    openBalance += deposit;
    cout << "Deposit" <<"            "<< deposit <<" Ct" <<"            " << openBalance << endl;
    out_stream << deposit;
}

if (letter == 'I')
{

    in_stream >> interest;
    openBalance += interest;
    cout << "Interest" <<"              "<< interest <<"            " << openBalance << endl;
    out_stream << interest;
 }

 if (openBalance < 1000)
 {
     cout << "Bank Costs" <<"           "<< bankCost <<"            " << openBalance <<"            " << bankCost << endl;
    openBalance -= bankCost;
    out_stream << bankCost;
  }

} while(!in_stream.eof());