balance brought forward

[sum abiut]

Hi,

I am working on an accounting app and i needed direction on how to go about calculating the balance brought for a particular day.

What i want to accomplish is being able to display the balance brought forward when the user select a date. i want to be able to display the transaction that happen in a particular date and the balance brought forward from the previous day.

currently i just sum up all the transaction that was done in and then minus the total sum to get the opening balance.

However when ever there is a movement in the account  the brought forward balance on different dates also change.

dailytransaction =Sum(dailytransactions)

openingbalance=totalsum

balancebroughforward=openingbalance-dailytransaction

how to i keep the balance brought forward for each day unchange whenever there is movement on an account each day.

cheer,