Created using remix-ide: Realtime Ethereum Contract Compiler and Runtime. Load this file by pasting this gists URL or ID at https://remix.ethereum.org/#version=soljson-v0.5.16+commit.9c3226ce.js&optimize=false&runs=200&gist=

CallCounter.sol

pragma solidity ^0.5.16;
contract Counter{
    uint private count = 10;
    uint public showc;
    function inc(uint num) public returns(uint){
        return count += num;
    }
    function getCount() public returns(uint){
        showc = count;
        return showc;
    }
}

contract CallCounter {
    // uint public count = 20;
    function callByAddr(address addr) public returns (uint){
        return Counter(addr).inc(2);
    }
}