Understanding the if and if...else decision controls
Solidity provides conditional code execution with the help of the if...else instructions. The general structure of if...else is as follows:
if (this condition/expression is true) {
   Execute the instructions here
}
else if (this condition/expression is true) {
   Execute the instructions here
}
else {
   Execute the instructions here
}
if and if...else are keywords in Solidity, and they inform the compiler that they contain a decision control condition – for example, if (a > 10). Here, if contains a condition that can evaluate as either true or false. If a > 10 evaluates to true, then the code instructions that follow in the pair of double-brackets, { and }, should be executed.
else is also a keyword that provides an alternate path if none of the previous conditions are true. It also contains a decision control instruction and executes the code instructions if...
