10-19 Exercise 3: Prints the number with its digits reversed

Question

Write a program that input four-digit number, then prints the number with its digits reversed .

寫一個輸入4位數字，反轉輸出這個數字的值

Example input: 

5455

Example output:

5545

Example input: 

5400

Example output:

45

Answer 1

Hidden content!
#include <stdlib.h>

using namespace std;

int main()
{
***** * ** **  ** * *****   ** x;
    * **      *       ** *    **   ***  * * * *  *
** *  **  * * * *  ** *** *  *  **** * ** *  **    * ****   * * ***  ***** * ***           
*** *  **** *    *      ***** * **** *     *******   * * *   *******   **  **  *
   * * *  * * *** *  ***   *   **   ** ** *  **   **    ** *  ** *   * * ** *** **    *****    ******* *           
* *  * ***   *   *  * *   **** ***** *  * ** *** * ****
 * **   *  ** ** ***  * ** *** * *   **    *   * ** * *  * *  * **  * *   **  ;
*  * * * *  * *** **  **** ***
  * * *    *** * * *  * **   **  0;
}

Comments

prog.c:3:1: error: unknown type name 'using'
 using namespace std;
 ^~~~~
prog.c:3:17: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'std'
 using namespace std;
                 ^~~
prog.c: In function 'main':
prog.c:7:5: error: unknown type name 'string'
     string x;
     ^~~~~~
prog.c:8:11: error: 'cin' undeclared (first use in this function)
     while(cin>>x){
           ^~~
prog.c:8:11: note: each undeclared identifier is reported only once for each function it appears in
prog.c:10:24: error: request for member 'length' in something not a structure or union
         for(int i=0;i<x.length();i++){
                        ^
prog.c:11:22: error: request for member 'length' in something not a structure or union
             re[i]=x[x.length()-i-1];
                      ^
prog.c:13:9: error: 'cout' undeclared (first use in this function)
         cout<<atoi(re)<<endl ;
         ^~~~
prog.c:13:25: error: 'endl' undeclared (first use in this function)
         cout<<atoi(re)<<endl ;
                         ^~~~

Answer 2

Hidden content!
#include <iostream>
#include  * * * *  *** 

using namespace std;

int main()
{
** *********  *****  * * *   x;
*  * **   ****** * * * ** * **  *    ** **** 
*   **  **   * ** * **    *  * * * * **  * ***  *** **  * *** *  *****  ** *   *  *            
    **   ** *   **  *   ** * * ***   * * ** * ** ***      * *  **** *** **   * 
* * ***  * ****  * *  ***    ***  *  ****    *  ********    *    *** ** *** *** **   * ** ***** *   ****  *        
 *****    **  * * *** *  **  ** ** * * *   * ***  
* *    *    * *** **   ** * * *** ****  **     ******* *  *  *   *   **        ****** ;
** **** ** ***  *   * *   ** * *  
*   *** **    * *  *** * *   ****    ***  0;
}

Comments

prog.c:1:20: fatal error: iostream: No such file or directory
 #include <iostream>
                    ^
compilation terminated.

Answer 3

Hidden content!
    * * ** **  **
*   * 
{
** * *  **  * * **   *
**   *  ***  ***   * **    
a =  ****
*     * *** * **  =  *  ***

c = *  *
***   ****     ** ** = ******

e = *** 
 ** *  *   *    **   =   ** 

g =   
 **    ** *   ****    **   =  

*   * = c;
  =  
 * =  ****

**  = *
  =  
** = ** *


*  * = * ******* **
*      ** *  *  ****** *

  ** **
}

Comments

prog.c: In function 'main':
prog.c:4:19: error: variable 'h' set but not used [-Werror=unused-but-set-variable]
 int a,b,c,d,e,f,g,h,v,swap,temp,sum;
                   ^
cc1: all warnings being treated as errors

Answer 4

Hidden content!
**    ** 
  
*          * *** *** *** ** *
** ** *  **** *  *  ** ***
a =       
** *****    **   * **  = **

c =  ** *
 *** **  ***  ****** * =   * 

e =  ****
*  *       **    ** ** =   * 

g =  * 
** * * **     *    =  

    = *
  = *
  = **

**  = *
  = **
* =    


** =    ** * ** * ***
** *      **** *   **  * *

*   * * 
 

Comments

prog.c: In function 'main':
prog.c:4:1: error: implicit declaration of function 'scanf' [-Werror=implicit-function-declaration]
 scanf("%d",&v);
 ^~~~~
prog.c:4:1: error: incompatible implicit declaration of built-in function 'scanf' [-Werror]
prog.c:4:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
prog.c:27:1: error: implicit declaration of function 'printf' [-Werror=implicit-function-declaration]
 printf("%d",sum);
 ^~~~~~
prog.c:27:1: error: incompatible implicit declaration of built-in function 'printf' [-Werror]
prog.c:27:1: note: include '<stdio.h>' or provide a declaration of 'printf'
prog.c:3:19: error: variable 'h' set but not used [-Werror=unused-but-set-variable]
 int a,b,c,d,e,f,g,h,v,swap,temp,sum;
                   ^
cc1: all warnings being treated as errors