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