cerc-io/solidity
16
0
Fork 0
mirror of https://github.com/ethereum/solidity synced 2023-10-03 13:03:40 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Fix mapping example.

Browse Source
This commit is contained in:
chriseth 2021-12-30 12:31:20 +01:00
parent 048a8f4d28
commit 0010027e17
1 changed files with 6 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
docs/types/mapping-types.rst
View File

@ -84,23 +84,24 @@ The example below uses ``_allowances`` to record the amount someone else is allo
} }
function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) { function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
require(_allowances[sender][msg.sender] >= amount, "ERC20: Allowance not high enough.");
_allowances[sender][msg.sender] -= amount;
_transfer(sender, recipient, amount); _transfer(sender, recipient, amount);
approve(sender, msg.sender, amount);
return true; return true;
} }
function approve(address owner, address spender, uint256 amount) public returns (bool) { function approve(address spender, uint256 amount) public returns (bool) {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address"); require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount; _allowances[msg.sender][spender] = amount;
emit Approval(owner, spender, amount); emit Approval(msg.sender, spender, amount);
return true; return true;
} }
function _transfer(address sender, address recipient, uint256 amount) internal { function _transfer(address sender, address recipient, uint256 amount) internal {
require(sender != address(0), "ERC20: transfer from the zero address"); require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address"); require(recipient != address(0), "ERC20: transfer to the zero address");
require(_balances[sender] >= amount, "ERC20: Not enough funds.");
_balances[sender] -= amount; _balances[sender] -= amount;
_balances[recipient] += amount; _balances[recipient] += amount;