Function input and output

Functions would not be that interesting if they didn't accept parameters and return values. Functions are made generic with the use of parameters and return values. Parameters can help by changing function execution and providing different execution paths. Solidity allows you to accept multiple parameters within a function; the only condition is that their identifiers should be uniquely named.

We will use the following code listing to understand functions and their different flavors of input parameters and return values:

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;; 
contract Parameters {
     function SingleIncomingParameter(int _data) public 
       pure returns (int _output) {
          return _data * 2;
     }
     function MultipleIncomingParameter(int _data...