#### QUESTION:

Given a non-negative integer num, return the number of steps to reduce it to zero. If the current number is even, you have to divide it by 2, otherwise, you have to subtract 1 from it.

Example 1:

```
Input: num = 14
Output: 6
Explanation:
Step 1) 14 is even; divide by 2 and obtain 7.
Step 2) 7 is odd; subtract 1 and obtain 6.
Step 3) 6 is even; divide by 2 and obtain 3.
Step 4) 3 is odd; subtract 1 and obtain 2.
Step 5) 2 is even; divide by 2 and obtain 1.
Step 6) 1 is odd; subtract 1 and obtain 0.
```

Example 2:

```
Input: num = 8
Output: 4
Explanation:
Step 1) 8 is even; divide by 2 and obtain 4.
Step 2) 4 is even; divide by 2 and obtain 2.
Step 3) 2 is even; divide by 2 and obtain 1.
Step 4) 1 is odd; subtract 1 and obtain 0.
Example 3:
Input: num = 123
Output: 12
```

Constraints:

```
0 <= num <= 10^6
```

#### EXPLANATION:

本来以为需要多么复杂的操作，如位运算啥的，发现其实只要模拟出这个过程，就可以得到结果了。

#### SOLUTION:

```
class Solution {
public int numberOfSteps (int num) {
int step = 0;
while (num!=0){
int tmp = num % 2 ;
if(tmp == 1){
num -= 1;
}else{
num = num/2;
}
step++;
}
return step;
}
}
```