Solidity Contracts – How to Import Contracts into Each Other

They are really similar, but not quite the same. The language is the same in many cases, and i think they were going for that, but there are even more fundamental differences that the fact that solidity contracts can store and send value and have a public address once deployed.

This question was asked before too, and there were some good answers. Is a smart contract analogous to an OOP class?

1.

function secfun(uint256 a) public view returns(uint256)

is declared as view, but tries modifying l

2. address useraddress;

is not declared public, so of course it cannot be returned.

Here is my working solution, I think you can make it from here on:

CallFunction.sol

    pragma solidity ^0.4.23;

import "./ArrayTes.sol";

contract CallFunction {

    address public useraddress;
    constructor(address _t) public {

        useraddress = _t;
    }

    function thirdfun(uint256 a) public view returns(uint256 c) {

        ArrayTes instanceuser = ArrayTes(useraddress);
        c = instanceuser.secfun(a);
        return c;
    }

}

ArrayTes.sol

pragma solidity ^0.4.23;

contract ArrayTes {

    function secfun(uint256 a) public pure returns(uint256) {
        uint l;
        l = l + a;
        return l;
    }
}

2_deploy_contracts.js

var ArrayTes = artifacts.require("./ArrayTes.sol");
var CallFunction = artifacts.require("./CallFunction.sol");
var cf;
module.exports = function(deployer) {

    deployer.deploy(ArrayTes).then(function() {
        return deployer.deploy(CallFunction, ArrayTes.address);
    }).then(function(instance){
      cf = instance;
      return cf.thirdfun.call(3).then(function(result){
        console.log("The number is: " + result.toNumber());
      });
    }).then(function(){
      return cf.useraddress.call().then(function(theAddress){
        console.log("The address is: " + theAddress);
      });
    })
};

Have fun !