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