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