public class StringExer {
public static void main(String[] args) {
StringExer exer = new StringExer();
System.out.println(exer.test1(" he ll o "));
}
/*
1.模拟一个trim方法，去除字符串两端的空格。
*/
public String test1(String str){
int startNum = 0;
int endNum = 0;
char[] arr = new char[str.length()];
for (int i = 0; i < arr.length; i++) {
if (arr[i] != ' '){
startNum = i;
break;
}
}
for (int j = arr.length; j < arr.length; j--) {
if (arr[j] != ' '){
endNum = j + 1;
break;
}
}
return str.substring(startNum,endNum);
}