剑指offer2

请实现一个函数，将一个字符串中的字符串空格替换成“%20”.例如：“We Are Happy”转化后为“We%20Are%20Happy”

思路：把字符串转化成字符数组，判断这个字符是不是空格，如果是空格的话就拼接字符“%20”,否则就直接拼接字符数组中的值

package demo2;

public class Main {

	public static void main(String[] args) {
		String str = "We Are Happy";
		String result = replaceSpace(str);
		System.out.println(result);
	}
	
	public static  String replaceSpace(String str){
		StringBuffer sb = new StringBuffer();
		char[] c = str.toCharArray();
		for (int i=0;i<c.length;i++) {
			if (c[i] == ' ') {
				sb.append("%20");
			} else {
				sb.append(c[i]);
			}
		}
		return sb.toString();
	}
	
}