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contracts...Test.sol

// pragma solidity means whick version of solidity youre using and we 
// are using Solidity version gt & eq version 0.7.0 and less than 0.9.0
pragma solidity >=0.7.0 <0.9.0;
// contract is keyword for creating Contract with named as TestContract
contract TestContract {
    // variable of the greeting
    string private greeting;
    
    // Initialize the greeting value to 'Hello!!'. 
    constructor() public {
        greeting = "Hello!!";        
    }
    
//    just like any other language we made setter / getter for setting values
    function setGreeting(string memory newGreeting) public {
        greeting = newGreeting;
    }
    
// public: greet function will be publicly accessed by users because of public modifiers 
// view:   means only viewable to value is gonna change
// return: tells a return type if string and memory tells that this is temporary data
// and it will not stay forever in block chain

    function greet() public view returns (string memory) {
        return greeting;
    }
}