Introduction to Java Programming编程题9.10<十进制转二进制>

/*
Enter a decimal number: 5
0B101
Enter a decimal number: 45
0B101101
 */
import java.util.Scanner;

public class DecimalToBinary {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        System.out.print("Enter a decimal number: ");
        int d = input.nextInt();
        String s = decimalToBinary(d);
        System.out.println("0B" + s); //编程语言中以“0B”开头的表示二进制数
    }

    public static String decimalToBinary(int d) {
        char[] ch = new char[1];
        StringBuilder stringBuilder = new StringBuilder();

        /* ch[0] = (char)(d % 2)输出结果为空白，Java不允许int类型
         * 直接转换为char字符。
         */
        do {
            ch[0] = (char) ('0' + d % 2);
            stringBuilder.append(ch);
        } while ((d /= 2) != 0);

        stringBuilder.reverse();

        return stringBuilder.toString();
    }
}