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