same errors (cannot find symbol) for two codes

[Joey Chen]

I am getting the same error for both these codes(both different). I been trying to figure out the problem and tried other possibilities but I just can't seem to crack it. Can someone lend me a hand and point me to the right direction.

Code 1:

cannot find symbol
symbol  : method isEmpty()
location: class java.lang.String[]
        if (args.isEmpty()) {
                ^
 
import java.util.* ;
 
class Echo1 {
    public static void main (String[] args) {
    if (args.isEmpty()) {
        System.exit(2);
        }
        else {
        for (String s: args) {
            System.out.println(s);
            System.exit(0);
        }
        }
    }
}
    

Code 2:

  cannot find symbol
symbol  : method pow(float,int)
location: class Numbers
        f = pow(num , 2);
// same error continues for other "pow" but i'm not displaying it because it's repetitive.
 
import java.lang.StrictMath;
 
class Numbers {
float f = 32.5f;
double d = 10.5;
int i = 5;
float sqr (float num) {
f = pow(num , 2);
}
double sqr (double num) {
d = pow(num , 2);
}
int sqr (int num) {
i = pow(num , 2);
}
float cube (float num) {
f = pow(num , 3);
}
double cube (double num) {
d = pow(num , 3);
}
int cube (int num) {
i = pow(num , 3);
}
}
 
  

Btw, code 2 isn't complete yet but I just wanted to compile the code I had to see if I encountered any errors so far which obviously I am.
[ September 12, 2007: Message edited by: Joey Chen ]

[Srikanth Basa]

You want to compile and run against which version ? anyway, here are a couple of fixes that you probably want to make.

   
class Echo1 {
    public static void main (String[] args) {
    if (args.length==0) {
        System.exit(2);
        }
        else {
        for (String s: args) {
            System.out.println(s);
            System.exit(0);
        }
        }
    }
}

    
 
 
class Numbers {
float f = 32.5f;
double d = 10.5;
int i = 5;
float sqr (float num) {
f = (float)StrictMath.pow(num , 2);
return f;
}
double sqr (double num) {
d = StrictMath.pow(num , 2);
return d;
}
int sqr (int num) {
i = (int)StrictMath.pow(num , 2);
return i;
}
float cube (float num) {
f = (float)StrictMath.pow(num , 3);
return f;
}
double cube (double num) {
d = StrictMath.pow(num , 3);
return d;
}
int cube (int num) {
i = (int)StrictMath.pow(num , 3);
return i;
}
}

[ September 12, 2007: Message edited by: Srikanth Basavaraju ]

[Joey Chen]

Ah. I see my mistakes now. Thank you, I definitely will remember these mistakes.

However, if I wanted to still use isEmpty() in the first code, how could I have used it correctly without the code getting complicated.

Also, is the length method in args.length from the java.lang.String? I am asking because I see a length() method in there but it has parenthesis after the length() so why wouldn't it be args.length()?
[ September 12, 2007: Message edited by: Joey Chen ]

[marc weber]

Originally posted by Joey Chen:
...is the length method in args.length from the java.lang.String? I am asking because I see a length() method in there but it has parenthesis after the length() so why wouldn't it be args.length()? ...

The variable "args" is an array (not a String), and "length" is a public field in an array.

This is described under JLS 10.7 Arrays.