25 lines
496 B
Solidity
25 lines
496 B
Solidity
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pragma solidity ^0.5.11;
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contract Counter {
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uint256 counter = 0;
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string internal constant ERROR_TOO_LOW = "COUNTER_TOO_LOW";
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event Changed(uint256 counter);
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event Added(uint256 counter);
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function add() public {
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counter++;
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emit Added(counter);
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emit Changed(counter);
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}
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function subtract() public {
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require(counter > 0, ERROR_TOO_LOW);
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counter--;
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emit Changed(counter);
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}
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function getCounter() public view returns (uint256) {
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return counter;
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}
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}
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