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