Thread: How i can solve this question? help me please ...

mport java.util.Scanner;


public class a{
public static void main(String[] args){
for (double i = 0; i <9; i++) {
if (r < o)
System.out.println("r is negative");
else
System.out.println("positive");
Scanner scan=new Scanner(System.in);

double a,r,p;

System.out.println("Enter value of radius:");
r=scan.nextDouble();

a=3.14*r*r ;
p=2*3.14*r;

System.out.println("Area= "+a);
System.out.println("Perimeter = "+p);
}
}
}








?? where is my mistake >?

ok where i have to but the if statement and why it is not working with my?

import java.util.Scanner;


public class a{
public static void main(String[] args){
for (double i = 0; i <9; i++) {

Scanner scan=new Scanner(System.in);

double a,r,p;

System.out.println("Enter value of radius:");
r=scan.nextDouble();

a=3.14*r*r ;
p=2*3.14*r;

System.out.println("Area= "+a);
System.out.println("Perimeter = "+p);
if ( r < o)
System.out.println("r is negative");
else
System.out.println("positive");
}
}
}


am using Dr java .. i understand what you say but am confusing

1 error found:
File: C:\Users\Quick age\Desktop\a.java [line: 21]
Error: C:\Users\Quick age\Desktop\a.java:21: cannot find symbol
symbol : variable o
location: class a


the console :
nothing appear because of the problem which is in the code

if ( r < o)
System.out.println("r is negative");
else
System.out.println("positive");

because if it is less than zero it will equal negative
can you help me to done this step if you allow ?
i have to done the program

thanks my frend but how i can stop the program when i unter negative number ?>

where i have to put System.exit(0);?

it is not working

import java.util.Scanner;


public class a{
public static void main(String[] args){
for (double i = 0; i <9; i++) {

Scanner scan=new Scanner(System.in);

double a,r,p;

System.out.println("Enter value of radius:");
r=scan.nextDouble();

a=3.14*r*r ;
p=2*3.14*r;

System.out.println("Area= "+a);
System.out.println("Perimeter = "+p);
if ( r < 0)

System.out.println("r is negative");
System.exit(0);

else
System.out.println("positive");

}
}
}

4 errors found:
File: C:\Users\Quick age\Desktop\a.java [line: 26]
Error: C:\Users\Quick age\Desktop\a.java:26: 'else' without 'if'
File: C:\Users\Quick age\Desktop\a.java [line: 27]
Error: C:\Users\Quick age\Desktop\a.java:27: <identifier> expected
File: C:\Users\Quick age\Desktop\a.java [line: 27]
Error: C:\Users\Quick age\Desktop\a.java:27: illegal start of type
File: C:\Users\Quick age\Desktop\a.java [line: 30]
Error: C:\Users\Quick age\Desktop\a.java:30: class, interface, or enum expected

is it ok now ?

import java.util.Scanner;


public class a{
public static void main(String[] args){
for (double i = 0; i <9; i++) {

Scanner scan=new Scanner(System.in);

double a,r,p;

System.out.println("Enter value of radius:");
r=scan.nextDouble();

a=3.14*r*r ;
p=2*3.14*r;

System.out.println("Area= "+a);
System.out.println("Perimeter = "+p);
if ( r < 0){

System.out.println("r is negative");
System.exit(0);
}
else
System.out.println("positive");

}
}
}

thank you very math my friend ok i will do it
it look show the result and close directly >>

Hi ,
One more thing that u can do is to use while loop and check for r being negative while(r>0) if so get the input from user and print the values of are a nad perimeter.
By the way ur area would come wrong.
Regards,
Devesh

thanks my dear i use your way and it successful thanks for you ...