利用接口做参数，写个计算器，能完成+-*/运算
（1）定义一个接口Compute含有一个方法int computer(int n,int m);
（2）设计四个类分别实现此接口，完成+-*/运算
（3）设计一个类UseCompute，含有方法：
public void useCom(Compute com, int one, int two)
此方法要求能够：1．用传递过来的对象调用computer方法完成运算
2．输出运算的结果
（4）设计一个测试类，调用UseCompute中的方法useCom来完成+-*/运算
package yunsuan;
public interface Compute {
int computer(int n,int m);
}
package yunsuan;
public class Jia implements Compute {
@Override
public int computer(int n, int m) //加法
{
int he;
he=n+m;
return he;
}
}
package yunsuan;
public class Jian implements Compute {
@Override
public int computer(int n, int m) {
int cha=n-m;
return cha;
}
}
package yunsuan;
public class Cheng implements Compute {
@Override
public int computer(int n, int m) {
int ji=n*m;
return ji;
}
}
package yunsuan;
public class Chu implements Compute {
@Override
public int computer(int n, int m) {
if(m==0)
{
System.out.println("被除数不能为0");
}
int shang=n/m;
return shang;
}
}
package yunsuan;
public class UseCompute {
public void useCom(Compute com, int one, int two)
{
System.out.println(com.computer(one, two));
}
}
package yunsuan;
public class E {
public static void main(String[] args) {
UseCompute u=new UseCompute();
System.out.print("1+3=");
u.useCom(new Jia(), 1, 3);
System.out.print("1-3=");
u.useCom(new Jian(), 1, 3);
System.out.print("1*3=");
u.useCom(new Cheng(), 1, 3);
System.out.print("1/3=");
u.useCom(new Chu(), 1, 3);
}
}