answer for 那那

[Steven_Tian]

import java.util.Scanner; // program use class Scanner

public class B9916025_hw05 // main method begins execution of Java
application
{
public static void main(String args[]) {
Scanner input = new Scanner(System.in); // create Scanner to obtain
String two = ""; // input from command window
do {
System.out.printf("\nPlease enter a binary integer : ");
two = input.next();
if (two.length() > 10) {
System.out
.printf("\nSorry!! This program can only calculate to the decade
1023.\n"
+ "That is you only can enter ten digits in the binary number.\n");
}else if (isBin(two)) {
System.out
.printf("\nThe integer that you entered is not a binary integer.
\n");
} else {
int ten = 0;
int binary = Integer.parseInt(two);
for (int i = 1; i <= two.length(); i++) {
if ((binary % Math.pow(10, i)) / Math.pow(10, i - 1) == 1) {
ten += Math.pow(2, i - 1);
binary = binary - binary % (int) (Math.pow(10, i));
} // end if
else if ((binary % Math.pow(10, i)) / Math.pow(10, i - 1) == 0)
continue;
} // end for
System.out.printf("\nThe decimal number is %d\n", ten);
} // end else
} while (two.length() > 10 || isBin(two));
} // end method main
public static boolean isBin(String str){
boolean r=false;
for(int i=0;i<str.length();i++){
char c=str.charAt(i);
if( c > '1' || c< '0'){
r=true;
break;
}
}
return r;
}
} // end class B9916025_hw06