Ch21 Calling an already deployed contract

1. Target Contract: A contract OtherContract is introduced with functions to manage a state variable (_x), accept Ether (ETH), and emit events. The contract has functions to return its balance, modify _x, and retrieve _x.
2. Contract-to-Contract Interaction: Different methods are shown for how to interact with the OtherContract using its address:

• Passing the contract address as an argument.
• Passing the contract itself as a reference.
• Creating a contract reference within a function.
• Sending ETH during contract function calls with payable functions.

Quiz Insights:

• Contracts calling other contracts help in code reuse but don't necessarily reduce gas costs.
• Calling functions of a deployed contract can be done using the contract's address and type (either the actual contract or its interface).
• Proper security practices are essential to prevent unauthorized changes to a contract’s state variables.

Ch22 Call

Call is a low-level member function for address type.