安卓实验电信二班310002831李硕Word下载.docx
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doublea,b,c;
doubleroot1,root2;
booleanboo;
publicSquareEquation(doublea,doubleb,doublec)
{
this.a=a;
this.b=b;
this.c=c;
if(a!
=0)
{
boo=true;
}
else
boo=false;
}
publicvoidgetRoots()
if(boo)
System.out.println("
是一元2次方程"
);
doubledisk=b*b-4*a*c;
if(disk>
root1=(-b+Math.sqrt(disk))/(2*a);
root2=(-b-Math.sqrt(disk))/(2*a);
System.out.printf("
方程的根:
%f,%f\n"
root1,root2);
方程没有实根\n"
不是一元2次方程"
publicvoidsetCoefficient(doublea,doubleb,doublec)
}
SunRise.java
//倒包即可
importtom.jiafei.*;
classSunRise
publicstaticvoidmain(Stringargs[])
SquareEquationequation=newSquareEquation(4,5,1);
equation.getRoots();
equation.setCoefficient(-3,4,5);
2、继承
按照前面介绍的使用Eclipse输入、编译、调试程序的步骤,输入下面程序并完成未实现的代码,然后编译、调试程序。
packagecom.Example;
publicclassPeople
{
protecteddoubleweight,height;
publicvoidspeakHello()
{
System.out.println("
yayawawa"
}
publicvoidaverageHeight()
{
height=173;
averageheight:
"
+height);
}
publicvoidaverageWeight()
weight=70;
averageweight:
+weight);
classChinaPeopleextendsPeople
//直接继承输出函数即可
publicvoidspeakHello()
System.out.println("
你好,吃了吗"
//直接调用输出函数
//只需改变数据值即可
height=168.78;
//单位是汉字,需要注意添加格式
System.out.println("
中国人的平均身高:
+height+"
厘米"
weight=65;
//直接继承输出函数,需要注意单位的添加方式
中国人的平均体重:
+weight+"
公斤"
publicvoidchinaGongfu()
//直接继承输出函数
坐如钟,站如松,睡如弓"
classAmericanPeopleextendsPeople
//直接继承输出函数
Howdoyoudo"
height=178.78;
//直接继承输出函数
美国人的平均身高:
//直接继承输出函数,并注意单位的添加
weight=75;
美国人的平均体重:
publicvoidamericanBoxing()
直拳、钩拳"
classBeijingPeopleextendsChinaPeople
//直接继承输出函数
您好"
//直接继承输出函数,并注意单位的添加
height=170.78;
北京人的平均身高:
publicvoidaverageWeight()
//直接继承输出函数,并注意单位的添加
weight=78;
北京人的平均体重:
}
publicvoidbeijingOpera()
唱腔,身段,把式,生旦净丑"
publicstaticclassExample
//这是本程序的主函数,程序直接来此运行,当需要计算的时候再调用上面的程序
publicstaticvoidmain(Stringargs[])
ChinaPeoplechinaPeople=newChinaPeople();
AmericanPeopleamericanPeople=newAmericanPeople();
BeijingPeoplebeijingPeople=newBeijingPeople();
chinaPeople.speakHello();
americanPeople.speakHello();
beijingPeople.speakHello();
chinaPeople.averageHeight();
americanPeople.averageHeight();
beijingPeople.averageHeight();
chinaPeople.averageWeight();
americanPeople.averageWeight();
beijingPeople.averageWeight();
chinaPeople.chinaGongfu();
americanPeople.americanBoxing();
beijingPeople.beijingOpera();
beijingPeople.chinaGongfu();
3、接口回调
按照前面介绍的使用Eclipse输入、编译、调试程序的步骤,输入下面程序并完成未实现的代码,然后编译、调试程序。
packagecom.lishuo;
interfaceComputerWeight
publicdoublecomputeWeight();
classTelevisionimplementsComputerWeight
//实现computeWeight()方法。
publicdoublecomputeWeight()
//调用return关键词
return1.0;
classComputerimplementsComputerWeight
//实现computeWeight()方法。
//调用return关键词
return2.0;
classWashMachineimplementsComputerWeight
//调用return关键词
return3.0;
classCar
{ComputerWeight[]goods;
doubletotalWeights=0;
Car(ComputerWeight[]goods)
this.goods=goods;
publicdoublegetTotalWeights()
totalWeights=0;
//计算totalWeights
//调用for函数进行计算
for(ComputerWeightgood:
goods)
totalWeights+=puteWeight();
returntotalWeights;
//这是本程序的主类,程序直接来此运行,当需要计算的时候,根据主类里面的指示去上面的方法里面去计算即可
publicclassRoad
{ComputerWeight[]goodsOne=newComputerWeight[50],
goodsTwo=newComputerWeight[22];
for(inti=0;
i<
goodsOne.length;
i++)
{if(i%3==0)
goodsOne[i]=newTelevision();
elseif(i%3==1)
goodsOne[i]=newComputer();
elseif(i%3==2)
goodsOne[i]=newWashMachine();
goodsTwo.length;
goodsTwo[i]=newTelevision();
goodsTwo[i]=newComputer();
goodsTwo[i]=newWashMachine();
Car大货车=newCar(goodsOne);
//输出结果
大货车载货物重量:
+大货车.getTotalWeights());
Car小货车=newCar(goodsTwo);
小货车载货物重量:
+小货车.getTotalWeights());