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