Mastering Blockchain Programming with Solidity

Reading a contract's ether balance

The address type has only one member property, that is, .balance. The syntax is as follows:

<address>.balance

.balance is a property; it is not a member function. This returns the current ether balance of an address as uint256 and is represented in wei. 

The following is an example to get the current ether balance of the caller who initiated function call:

//This will return Ether balance of function caller. uint256 balanceInWei = msg.sender.balance;

One thing to notice here is that if you are using the msg.sender.balance statement in your code, then it will return the current balance after deducting the maximum transaction fee required for the current call. For example, if an account X had a balance of ...