>I want to compare two variable which is in character type. These two variables contain hours . I want to know which one is the most recent
You may also want to consider using datetime values.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)