Ruby program to check a given sentence for a given set of simple grammer rules. A simple sentence if syntactically correct if it fulfills given rules. The following are given rules.

1. Sentence must start with a Uppercase character (e.g. Noun/ I/ We/ He / She / etc.)
2. Then lowercase character follows.
3. There must be spaces between words.
4. Then the sentence must end with a full stop(.) after a word.
5. Two continuous spaces are not allowed.
6. Two continuous upper case characters are not allowed.
7. However the sentence can end after an upper case character.

Example input and output

Please enter a sentence to check grammer mistake

welcome to DEMO for checking grammer mistake

Given sentence is wrong because

First character should start with upper case

Two spaces are not allowed

Two Uppercase characters are not allowed continuously

Sentence should end with full stop

Please enter a sentence to check grammer mistake

Welcome to demo for checking Grammer mistakE.

Given sentence is correct, sentence does not have grammer mistake