java课程作业

Greeter

1.Greeter

public class Greeter{
    private static void greet(int cols) {
        String str="";
        for(int i=1;i<=cols;i++) str+="*";
        System.out.println(str);
    }
    private static void greet(int cols,String words) {
        int len=words.length();
        String str="*";
        int blank=29-len>>1;
        for(int i=1;i<=blank;i++) {
            str+=" ";
        }
        str+=words;
        for(int i=1;i<=blank;i++) {
            str+=" ";
        }
        str+="*";
        System.out.println(str);
    }
    public static void main(String[] args) {
        greet(31);
        greet(31," ");
        greet(31,"Welcome to Java");
        greet(31," ");
        greet(31,"Nanjing Forestry University");
        greet(31," ");
        greet(31);
    }
}

2.Greeter2

package Greeter;

public class Greeter2 {
    private static void greet(int cols) {
        for(int i=1;i<=cols;i++) System.out.print("*");
        System.out.println("");
    }
    private static void greet(int cols,String words) {
        int len=words.length();
        System.out.print("*");
        int blank=29-len>>1;
        for(int i=1;i<=blank;i++) {
            System.out.print(" ");
        }
        System.out.print(words);
        for(int i=1;i<=blank;i++) {
            System.out.print(" ");
        }
        System.out.println("*");
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        greet(31);
        greet(31," ");
        greet(31,"Welcome to Java");
        greet(31," ");
        greet(31,"Nanjing Forestry University");
        greet(31," ");
        greet(31);
    }

}

Factorial

package Factorial;
public class Factorial {
    static long last_ans=0;
    private static long calculate(int n) {
        long ans=1;
        for(int i=1;i<=n;++i) {
            ans*=i;
        }
        last_ans=ans;
        return ans;
    }
    private static long getFact() {
            return last_ans;
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println("5!="+calculate(5));
    }

}

BreakJail

BreakJail

BreakJail2