Ribbit project experiments ground

call_another_contract.sol

// this file is an example of calling other contracts

pragma solidity ^0.4.0;

contract Test {
    mapping (string => uint) data;
    address public previousContractAddress;
    Test previousContract;
    
    constructor(address previousContractAddress_) public {
        previousContractAddress = previousContractAddress_;
        previousContract = Test(previousContractAddress);
    }
    
    function getData(string key) external constant returns (uint) {
        uint result = data[key];
        if (previousContractAddress != address(0)) {
            result += previousContract.getData(key);
        }
        return result;
    }
    
    function incrementData(string key, uint delta) external {
        data[key] = data[key] + delta;
    }
}

/*

Suppose I firstly created an smart contract Test() and get an address 0xa6673deb97897b9e3e6f2cd69826141c50cd31f8

.incrementData("x", 1) 
.getData("x")  => {"x": 1}
.incrementData("x", 1)
.getData("x")  => {"x": 2}

Then I create another contract Test(0xa6673deb97897b9e3e6f2cd69826141c50cd31f8) 
and get an address 0x6b0a8e29a932eaa75a1069b1915ceadf1fd3c5cb

.getData("x")  => {"x": 2}

So you see it calls the previous contract.

*/