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