12-07 Exercise 2: Function num_digits

Question

Write a function num_digits(n) that returns the number of digits in n ( a positive integer). Hint: to determine the number of digits in a number n, divide it by 10 repeatedly. when n reaches 0, the number of divisions indicates how many digits n originally had.

寫一個num_digits(n)函數 計算n有幾位數

#include <stdio.h>
int num_digits(int n)
{
   /*INSERT YOUR CODE HERE*/

   /*在這裡寫你的程式*/
   /*END OF YOUR CODE*/
}

int main(void)
{
   int n;
   scanf("%d", &n);
   printf("%d has %d digit(s)",n,num_digits(n));
   return 0;
}

Please complete this program by only insert your code between those tags:

   /*INSERT YOUR CODE HERE*/ 
   /*END OF YOUR CODE*/

Example input

12347

Example output

12347 has 5 digit(s)

Remember: You may correct the cases, but your code always be revised!

Answer 1

Hidden content!
#include <stdio.h>
int num_digits(int n)
{
 *      ** ***  * ***  YOUR CODE HERE*/

**   *  * * **    *** * **** ** digits=0,i,neg=0;
* **      **  * *     ** ***  * long int pow=1;
** * ** ***  *    **   ** ********  ** (n<0){
* *** **    * *  *** *******   * **   ****  * *  
  * **  ******* **  *    *     ** ***** ** * ** *     * *** * 
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  ** *    **  ***  * *** **
***  * **       **  *   *   **  (n==0){digits++;}
 ****** * * * *********    * (neg==1){n=n*-1;}
 **** * * ***  ** *  *   ****    digits;
 ** * ***** * ***  * ***   * ******  
**  **** * ** *   *    **  OF YOUR CODE*/
}

int main(void)
{
   int n;
** **      * **    ***** ****  * ***   **** &n);
 *** ***     *  *** ***  *  *** *** has %d ** * ** * ** *  *  ***
*     *** **  * *      ** 0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 2

Hidden content!
#include <stdio.h>
int num_digits(int n)
{
* ** ***    *** **  i=0;
*  ****  ***  ** * **  **   *
**  *    * ** *   *
** **  * ***  *** * *** * ***  **   *    *  * *****
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********* ** * *   *  i;
 *** ***  *** ******  * ** * YOUR CODE HERE*/

 * * *   * *  *    ***** **  **  *
     *   **  * ****  * * OF YOUR CODE*/
}

int main(void)
{
**  ****   *** * *  * *  n;
  **  *** *** ******** **** ** *** * *  &n);
**  *** ** ** *******      *  ** * * has %d *  * * ****** * **    * *****
**  ** *****    **  *  0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 3

Hidden content!
#include <stdio.h>
int num_digits(int n)
{
***    **        ***    *** *  counter=1;
 *     *  * * *   **  **  *   *    *   ** * * 
***** ***** ** * * *   * * * ******  *** *** **   **** * *
*   *  **  *    *   *   ******   *** *** *** *  **    ***
 **  * *** ** * **   * 
* * *** *   *   *******  *    * counter;
}

int main(void)
{
* **  ****** **   * *   * n;
    ** * **    *****  * ** ****  *    &n);
 *  ** *** *  *  ** * * *   ** has %d ***    ******    ***** 
*  **   ** *****  *  ** *  0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 4

Hidden content!
#include <stdio.h>
int num_digits(int n)
{
*  *    ***** * *  * ***   * * *  * *  i;
 * * *** *  ** ***   ** *   *   * {
* **  *  *  * ***  *    *  *****  *  * * ** *** **  * *  ***  * 
   ***  ** * *      ***** ***  *    * * * **   ***   *** break;
 * * ** ** **  * ** ** ***   * *  * *   * *   * *       **  
    ** **  ** * * **    *    *
* ** * *  **  *** ** * *   * i;
}

int main(void)
{
** *  ***  ****** ****   n;
* ****    *  ** *** ** ** * *** ***** &n);
  * *  *   ***     * **  **      has %d * * *     *   *  *    *
****    ** * ****** *  0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 5

Hidden content!
#include ** * *  * *** *   
int num_digits(int n)
{
* * ********  *** *   i;
*** ** * *   **   **    * * *   *   = 0;n!=0;i++)
**********  **      **    *   
  * ** **      **      *  *   *** *  *    ***   ***   = n / 10;
  ** * *  * ** *** ***** **   
 *** ******* **  * ***  **  **  ** i;
}

int main(void)
{
     *   *  *  *   *  n;
*  **  **   ** *  * **  *  *   ****      * &n);
* *****   ***  * *
* **     * *** *****     *** * has %d   ** ** ** * *   ***  
   **    * * *    *
 * **  * *  * * ***  *   0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output