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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 *  ***  **  * * * ** ** ** (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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 * *  ** * * ** *         *** YOUR CODE HERE*/

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

int main(void)
{
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  ** * *  * **  **      *   * * * * 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;
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* *   *** ** * ***  **  *       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