// NAC智能合约
contract Token {
    storage {
        balances: map<Address, u128>,
        total_supply: u128,
    }
    
    constructor(initial_supply: u128) {
        self.total_supply = initial_supply;
        self.balances[msg.sender] = initial_supply;
    }
    
    pub fn transfer(to: Address, amount: u128) -> bool {
        require(self.balances[msg.sender] >= amount, "Insufficient balance");
        self.balances[msg.sender] -= amount;
        self.balances[to] += amount;
        true
    }
    
    pub fn balance_of(account: Address) -> u128 {
        self.balances[account]
    }
}