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