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