any code?

first you need to learn file I/O...

clarify you data file... which one is it?

ACCT# Int R Balance Months Deposit WithD Deposit
3456 0.03 1256.89 4 0.00 56.00 100.00
3456 0.03 1256.89 4 0.00 56.00 100.00
3456 0.03 1256.89 4 0.00 56.00 100.00

or

ACCT# Int R Balance Months Deposit WithD Deposit
3456 0.03 1256.89 4 0.00 56.00 100.00
ACCT# Int R Balance Months Deposit WithD Deposit
3456 0.03 1256.89 4 0.00 56.00 100.00
ACCT# Int R Balance Months Deposit WithD Deposit
3456 0.03 1256.89 4 0.00 56.00 100.00

or

3456 0.03 1256.89 4 0.00 56.00 100.00
3456 0.03 1256.89 4 0.00 56.00 100.00
3456 0.03 1256.89 4 0.00 56.00 100.00