Java 负数转换成二进制

对于十进制负整数N，求其负二进制表示。例如 1*1+1*-2+1*4+0*-8+1*16+1*-32=-13,所以10进制的-13 = 负二进制的110111

public static void main(String[] args) {

int num = -13;
String str = minusDecimalismToBinary(num);
System.out.println(str);
int a = 6;
a += a-=a*a;
System.out.println(a);
baseDataType();

}
public static String minusDecimalismToBinary(int num){
StringBuffer sb = new StringBuffer();
int temp = -num;
int counter = 0;
while(temp!=0){
counter++;
sb.append(temp%2);
if((counter+1)%2==0){
temp += temp/2*-1;
}else{
temp = temp/2;
}
};
return sb.toString();

}

}