Performance and Gas Implications: uint vs int in Solidity Memory Variables

Question

I am working on a Solidity smart contract and am considering the use of uint and int data types for memory variables. I have specific use-cases like reverse looping, where using int seems to produce cleaner code.

My questions are:

1. Are there any performance differences between using uint and int in terms of computational cost and gas consumption?
2. Are there best practices around the choice of these data types in Solidity, especially considering the web3 development space?

Answer 1

The main difference between uint and int is that uint only accepts positive values, while int accepts positive and negative values. They both store a 256-bit size value and as such, have the same storage cost.

The gas cost would vary depending on the operations you will make. Generally speaking gas cost may be higher for int if negative numbers are involved because handling negative numbers in smart contracts can be more complex.

To summarize, uint is often preferred for cases where you want to ensure that a variable is always non-negative, while for doing arithmetic operations, int is better.