public class Demo {

 public static void main(String[] args) {
 Strategy strategy1 = new StrategyAdd();
 Strategy strategy2 = new StrategyDiv();
 Context context1 = new Context(strategy1);
 context1.execute(10, 5);
 context1 = new Context(strategy2);
 context1.execute(10, 5);
 }
}

interface Strategy{
 public void doOperation(int num1,int num2);
}

class StrategyAdd implements Strategy{

 public void doOperation(int num1, int num2) {
 System.out.println("执行加法");
 System.out.println(num1+"+"+num2+"="+(num1+num2));
 }
 
}

class StrategySub implements Strategy{

 public void doOperation(int num1, int num2) {
 System.out.println("执行减法");
 System.out.println(num1+"-"+num2+"="+(num1-num2));
 }
 
}

class StrategyMul implements Strategy{

 public void doOperation(int num1, int num2) {
 System.out.println("执行乘法");
 System.out.println(num1+"*"+num2+"="+(num1*num2));
 }
 
}

class StrategyDiv implements Strategy{

 public void doOperation(int num1, int num2) {
 System.out.println("执行除法");
 System.out.println(num1+"/"+num2+"="+(num1/num2));
 }
 
}

class Context{
 private Strategy strategy;
 
 public Context(Strategy strategy) {
 this.strategy = strategy;
 }
 
 public void execute(int num1,int num2){
 strategy.doOperation(num1, num2);
 }
}