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;
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 **      ****  ** * *** ** *    ** **   **   ***   * **  *   *      * *                  
*  *** *** * *** ** *          **  ** *** *      * * * *            * *
*  *      ** ***   ***   ****  *** * *** ****  ** ** **    * ***   *****   * * * * *    *   ** ***  * ** *       
  ****  *  *   **  ***  * *    ** **** **   ** * *****  *  ***
 *    * *    * **   *  *   *** ** *  ** **** *    * *** * *  ***   *** **  **   * *** ;
 *  * **   ***   **  ***  *  
  ** ** * **  ***  *  **** * ** *  * 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