A function is basically a group of code that can be reused anywhere in the program, which generally saves the excessive use of memory and decreases the runtime of the program. Creating a function reduces the need of writing the same code over and over again.
Syntax -
function function_name(parameter_list) scope returns(return_type) {
// block of code
}eg-
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
contract MyContract {
function add() public view returns (uint256) {
uint256 num1 = 10;
uint256 num2 = 16;
uint256 sum = num1 + num2;
return sum;
}
function sqrt(uint256 num) public pure returns (uint256) {
num = num**2;
return num;
}
}view in a function ensures that they will not modify the state of the function.