public static void main(String args[]) {
//do while

        int sum = 0; //当前之和

        int i = 1; //加数

        do {

        if (i%2==0){

        sum+=i;

        }

        i++;

        }while (i<=100);

        System.out.println(sum);

    }

}

public static void main(String args[]) {
//while

             int res=0;

             int a=1;

             while(a<101) {

                 if(a%2==0) {

                     res+=a;

                 }

                 a++;

             }

             System.out.println(res);

}

}

    public static void main(String []args){

// for

        int sum=0;

        for(int i=1;i<101;i++){

            if(i%2==0){

            sum+=i;

            }

        }

        System.out.println(sum);

        }

}