项目一----整数和。偶数和。阶乘和。

public class Sumn {  
public static void main(String args[]){  
    System.out.println("整数和");  
    Sum s1=new Sum();  
    s1.print();  
    System.out.println("偶数和");  
    Sumn1 s2=new Sumn1();  
    s2.print();  
    System.out.println("阶乘和");  
    Sumn2 s3=new Sumn2();  
    s3.print();  
}   
}  
  
  
public class Sum {  
int sum=0;  
int n;  
 public int sum(int n){  
    int x=0;  
    for(int i=1;i<=n;i++){  
        x=x+i;  
    }  
    int s=x;  
    return s;  
}  
public void print(){  
    System.out.println(sum(10));  
}  
}  
  
  
  
public class Sumn1 {  
int sumn=0;  
int n;  
public int sumn(int n){  
    int x=0;  
        for(int i=2;i<=n;i=i+2){  
            x=x+i;  
        }  
        int s=x;  
        return s;  
    }  
    public void print(){  
        System.out.println(sumn(10));  
    }  
    }  
  
  
  
public class Sumn2 {  
      
     public int sumn2(int n){  
        int x=1;  
        for(int i=1;i<=n;i++){  
            x=x*i;  
        }  
        int s=x;  
        return s;  
    }  
    public void print(){  
        System.out.println(sumn2(10));  
    }  
    }