What Implicit arguments are in Cairo lang?

Implicit argument refers to the arguments which are passed in the curly bracket of the functions of starknet contracts.

Every starknet contract has storage variable. To accurately compute the precise memory address of storage variables, these implicit arguments come in handy. syscall_ptr, pedersen_ptr, and range_check_ptr are the most commonly used implicit arguments:

• syscall_ptr: available to StarkNet contracts (not available in Cairo programs), allows the code to invoke system calls for reads and writes -
• pedersen_ptr: computes the Pedersen hash function especially when reading from storage maps.
• range_check_ptr: ensures valid comparison of integers

// This function increases the balance by the given amount.
// syscall_ptr, pedersen_ptr, range_check_ptr are the implicit arguments here
@external
func increase_balance{
    syscall_ptr: felt*,
    pedersen_ptr: HashBuiltin*,
    range_check_ptr,
}(amount: felt) {
    let (res) = balance.read();
    balance.write(res + amount);
    return ();
}