What are the differences between pure and impure functions?

Some of the major differences between pure and impure function are as below,

| Pure function | Impure function |

| ----------------------------------- | ---------------------------------------------------------------------- |

| It has no side effects | It causes side effects |

| It is always return the same result | It returns different result on each call |

| Easy to read and debug | Difficult to read and debug because they are affected by external code |