Replace all space in a string with '%20'
Problem
Write a method to replace all space in a string with '%2d'. You may assume that the string has sufficient space at the end of the string to hold the additional character, and that you are given the true length of the string.
[example]
ab_cd → ab%20cd
How to Solve
By editing the string starting from end to head, It is not necessary to consider of overwriting.
