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