[Solidity] How to write logical operators (and/or)?

This section explains how to write logical operators (and/or) in Solidity.

Syntax

The following is how to write logical operators (and/or) in Solidity.

And (logical conjunction)

"And (logical conjunction)" is written with && followed by two ampersands (&).

condition 1 && condition 2

Or (logical disjunction)

"Or (logical disjunction)" is written with || followed by two vertical bars (|).

condition 1 || condition 2

To combine multiple conditions

To group multiple conditions together, enclose the clusters of conditions in parentheses (()).

(condition 1 && condition 2) && (condition 3 || condition 4)

Sample Code

// SPDX-License-Identifier: GPL-3.0
 
pragma solidity >=0.7.0 <0.9.0;

contract Test {
    
    function sum(uint x, uint y) public pure returns(uint) {
        uint sum;

        // x > 0 and y > 0
        if (x > 0 && y > 0) {

            // x >= 100 or y >= 100
            if (x >= 100 || y >= 100) { revert("values must be less than 100"); }

            sum = x + y;
        }
        
        return sum;
    }

}

Solidity has a unique syntax, but the logical operators are the same as in many other programming languages!