UC知道java中创建类并编写应用程序,请高手指点,初学,请帮忙指出错误
来源：百度知道 编辑：UC知道 时间：2024/06/06 10:39:02
package javaapplication10;
class Equation
{double a,b,c;
Equation()
{a=0;
b=0;
c=0;
}
Equation(double m,double n,double k)
{a=m;
b=n;
c=k;
}
void setEquation(double m,double n,double k)
{a=m;
b=n;
c=k;
}
void ELV(double m,double n,double k)
{double d,x1,x2;
d=n*n-4*m*k;
if(d>=0)
{x1=(-n+Math.sqrt(d))/(2*m);
x2=(-n-Math.sqrt(d))/(2*m);
System.out.println("x1="+x1);
System.out.println("x2="+x2);
}
else{System.out.println("There is no result");}
double getA();
double getB();
double getC();
}
import java.lang.Math;
class Task {
public void main(String[] args) {
Equation t=new Equation();
t.setEquation("2,6,8");
System.out.println(t.getA()+"x*X"+t.getB()+"x"+t.getC());
t.ELV("2,6,8");
}
}
改后如
class Equation
{double a,b,c;
Equation()
{a=0;
b=0;
c=0;
}
Equation(double m,double n,double k)
{a=m;
b=n;
c=k;
}
void setEquation(double m,double n,double k)
{a=m;
b=n;
c=k;
}
void ELV(double m,double n,double k)
{double d,x1,x2;
d=n*n-4*m*k;
if(d>=0)
{x1=(-n+Math.sqrt(d))/(2*m);
x2=(-n-Math.sqrt(d))/(2*m);
System.out.println("x1="+x1);
System.out.println("x2="+x2);
}
else{System.out.println("There is no result");}
double getA();
double getB();
double getC();
}
import java.lang.Math;
class Task {
public void main(String[] args) {
Equation t=new Equation();
t.setEquation("2,6,8");
System.out.println(t.getA()+"x*X"+t.getB()+"x"+t.getC());
t.ELV("2,6,8");
}
}
改后如
错语有很多啊,
else{System.out.println("There is no result");} 大括号少一个职 }
double getA();
double getB();
double getC();
是抽像方法,没有实现,如果是特意这么写的话,类需要声明abstract,声明成abstract的类,不能够实例化
t.setEquation("2,6,8"); 方法调用错误,参数类型和个数都不对
.setEquation("2,6,8"); 方法调用错误,参数类型和个数都不对
import 语名要写在文件上方 package 的下面
class Task
如果您想执行这个 static main 方法,这个类必须是public 的,如果一个.java文件有多个类,只能有一个public 类,且这个.java 文件的名字是这个public 类的类名
public void main
应该是public static void main
更改后的,复制就行了
import java.lang.Math;
class Equation
{double a,b,c;
Equation()
{a=0;
b=0;
c=0;
}
Equation(double m,double n,double k)
{a=m;
b=n;
c=k;
}
void setEquation(double m,double n,double k)
{a=m;
b=n;
c=k;
}
void ELV(double m,double n,double k)
{double d,x1,x2;
d=n*n-4*m*k;