First project in Solidity

Create the contract that recieve the data and retrive the data. - Be able to do following 1. Receive the information, 2. Store the inforamtion, 3. Show the information

pragma solidity >=0.8.2 <0.9.0;
// create the contract that recieve the data and retrive the data.
// be able to do following
//1. receive the information, 2. store the inforamtion, 3. show the information

contract simpleStorage{   // our contract name is simpleStorage
    uint storevalue;   // variables are the reserved memory location to store value.
    // Function is a group of resueable code that can be used anywhere in our application. They perform a specific task.
    // For this contract we need two function. One is to set the value and another is to get the value.
    // to make a function, "Funtion" keyword is used.
    function set(uint _storedvalue) public {    // here public enables the visibility so that function can be call from outside the function.
        storevalue= _storedvalue;               
    }
    function get() public view returns(uint){// view is modifier which prevent the function to change the state.
        return storevalue;                    // reuturns specifies the return type of the function.
    }
}

• pragma solidity ...;:
  • The pragma keyword is a directive that provides additional information to the compiler. In this case, it’s used to specify the version of Solidity that should be used to compile the contract.
  • solidity indicates that this pragma is specifically for Solidity, the programming language used to write smart contracts on the Ethereum blockchain.
• >=0.8.2:
  • >= means “greater than or equal to.”
  • 0.8.2 refers to version 0.8.2 of the Solidity compiler.
  • This part of the pragma specifies that the contract can be compiled with Solidity version 0.8.2 or any newer version.
• <0.9.0:
  • < means “less than.”
  • 0.9.0 refers to version 0.9.0 of the Solidity compiler.
  • This part of the pragma specifies that the contract cannot be compiled with Solidity version 0.9.0 or any later version.

Detailed Explanation:

1. Contract Declaration:
   • contract simpleStorage { ... }:
     • This declares a new contract named simpleStorage. A contract in Solidity is similar to a class in object-oriented programming and contains state variables, functions, and other types of data.
2. State Variable:
   • uint storevalue;:
     • storevalue is a state variable of type uint (unsigned integer), which is stored on the blockchain. This variable holds the value that is set by the set function and retrieved by the get function.
     • State variables are persistent, meaning their values are stored on the blockchain and persist between function calls.
3. Function Definition:
   • set function:
     • function set(uint _storedvalue) public { ... }:
       • function is the keyword used to define a function.
       • set is the name of the function.
       • The function takes one argument, _storedvalue, of type uint.
       • The public keyword makes the function accessible from outside the contract.
       • Inside the function, the value passed to _storedvalue is assigned to the state variable storevalue.
   • get function:
     • function get() public view returns (uint) { ... }:
       • function is the keyword used to define a function.
       • get is the name of the function.
       • The function does not take any arguments.
       • The public keyword makes the function accessible from outside the contract.
       • The view modifier indicates that the function will not modify the contract’s state (i.e., it will not change any state variables).
       • returns (uint) specifies that the function returns a value of type uint.
       • The function returns the value stored in storevalue.

Summary:

• State Variable (storevalue): Stores an unsigned integer value that persists on the blockchain.
• set Function: Allows the user to set the value of storevalue.
• get Function: Allows the user to retrieve the value of storevalue without modifying the blockchain state.