Mastering Blockchain Programming with Solidity

Solidity version with pragma

Each Solidity contract/library source file should have the version of Solidity compiler specified. The version of the compiler should be specified first thing in the source file. The following is an example of how to specify the Solidity version:

pragma solidity ^0.4.4;

If a source file is of this version, it means the file will compile with 0.4.4 and higher versions in the 0.4.x branch, up to version 0.5.0 where 0.5.0 is not included.

It is recommended that the Solidity version should be locked and specified without the ^ (caret) sign, as follows:

pragma solidity 0.4.4;

This ensures that the specific compiler version will always be used, using which code is tested most. It also prevents the code from exhibiting ...