1. Some of the number systems used frequently include binary, octal, decimal and hexadecimal systems. Some sample numbers:
base 10 base 2 base 8 base 16
0 0 0 0
1 1 1 1
2 10 2 2
7 111 7 7
8 1000 10 8
9 1001 11 9
10 1010 12 A
11 1011 13 B
15 1111 17 F
16 10000 20 10
Look up web sites like http://www.tutorialspoint.com/computer_fundamentals/computer_number_system.htm
for more information about these systems.
Write and implement the following Java methods:
bToD(String b) //convert binary string b to an equivalent decimal string.
bToO(String b) //convert binary string b to an equivalent octal string.
bToH(String b) //convert binary string b to an equivalent hexadecimal string.
dToB(String d) //convert decimal string d to an equivalent binary string.
oToB(String o) //convert octal string o to an equivalent binary string.
hToB(String h) //convert hexadecimal string h to an equivalent binary string.
convert(int baseFrom, int baseTo, String n) // method to convert n given in baseFrom system to an equivalent number in baseTo system calling two of the above methods needed for conversion. If baseFrom = 10 and baseTo = 16, for example, method convert() will call dToB() followed by bToH() . You may assume that variables baseFrom and baseTo hold 2,8,10, or 16 only, and string n holds a number written in baseFrom system.
* Call the following methods(done in Hw9) from bToD(String b) and dToB(String d) methods appropriately:
String multiply2(String n) { //return 2*n
String r = “”;
int c = 0;
for (int i = n.length()-1; i >= 0; i–) {
int p = (n.charAt(i)-‘0’)*2+c;
c = p/10;
r = p%10+r;
}
if (c > 0)
r = c+r;
return r;
}
String divide2(String n) { //return n/2
String r = “”;
int b = 0;
int i = 0;
if (n.charAt(0) < ‘2’) {
b = 1;
i = 1;
}
for (; i < n.length(); i++) {
int p = (n.charAt(i)-‘0’)+b*10;
b = p%2;
r += p/2;
}
if (r.length() == 0)
r = “0”;
return r;
}
The other four methods can be directly implemented manipulating input strings as illustrated in this example:
101100011010112 = 261538 = 2C6B16
* Note that input and output numbers can be very long and converting them to int or long type before base conversion will cause an overflow error.
* No built-in class or method is allowed to use in this project except:
.next(), .nextLine(), .nextInt(), .nextLong(), .nextDouble(), .nextFloat() in Scanner class;
.length(), .charAt(), .indexOf(), .substring(), .comparedTo(), .equals() in String class;
.max(), .min(), .pow(), .sqrt(), .round(), .floor(), .ceil() in Math class.
.parseInt(), .toString() in Integer class.
* Your main method should use an appropriate loop or menu to test the above methods repeatedly.
