Solidity program to demonstrate how modifying storage items is expensive

StorageVariableDemo.sol

// Solidity program to demonstrate
// how modifying storage items is expensive
pragma solidity ^ 0.8.5;   
   
contract StorageVariableDemo
{
    uint public temp;
 
   /*
   * @description:Below function runs the for loop 100 times and updates
   * storage variable temp each time.
   */
    function expensiveFunction() external {
        for (uint i = 0; i < 100; i++){
            temp++;
        }
    }
	
   /*
   * @description: Below function runs the for loop 100 times and 
   * memory variable 100 times. This memory variable is then assigned back to temp.
   */
    function cheaperFunction() external {
        uint j = temp;
        for (uint i = 0; i < 100; i++){
            j++;
        }
        temp = j;
    }

}