java源码帮忙写下JAVA的源码

帮忙写下JAVA的源码

package firstJava; public class Grade { private int i; public Grade(int i) { super(); this.i = i; } public void toGrades(){ if(i>=90){ System.out.print("A"); }else if(i>=80){ System.out.print("B"); }else if (i>=70){ System.out.print("C"); }else { System.out.print("D"); } } public static void main(String[] args) { Grade g = new Grade(78); g.toGrades(); } }