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