As @stellari says,"our solution is very practical, but note that what your interviewer wants to hear more about is probably how you would deal with this problem on a lower level, without the help of those standard library functions. If you give an answer like this, then your interviewer will probably ask you to implement two more functions: trim and lastIndexOf."

```
public static int lengthOfLastWord(String s) {
int a=0;
for(int i=s.length()-1;i>=0;i--){
if(s.charAt(i)!=' '){
a++;
}else if(a>0){
break;
}
}
return a;
}
```