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