How to print value inside solidity function?

Question

I am new to solidity. I want to print a value of w and h inside rectangle function. how can I do that?

contract ShapeCalculator{
    function rectangle(uint w, uint h) returns (uint s, uint p) {
        //print value of w and h
        s = w * h;
        p = 2 * (w + h);
    }
} 

Answer 1

You can emit events.

pragma solidity ^0.4.21;

contract ShapeCalculator{
    function rectangle(uint256 w, uint256 h) public returns (uint256 s, uint256 p) {
        //print value of w and h
        emit Width(w);
        emit Height(h);

        s = w * h;
        p = 2 * (w + h);
    }

    event Width(uint256 w);
    event Height(uint256 h);
} 

You will see these events generated when the transaction is mined

[
    {
        "topic": "0xd9fe7dbbe8bd8e307a7710abb04dfbe406ccdc67a6aff083673fc25c8d9bcd47",
        "event": "Width",
        "args": [
            "1"
        ]
    },
    {
        "topic": "0xff7a085d76b69acdcd09df67f894435c0a628ed4da9d2180e85f4a5b4dbad030",
        "event": "Height",
        "args": [
            "5"
        ]
    }
]

Contract gist https://gist.github.com/cleanunicorn/500e53b86825c391b9d7947cf0c24d00