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;
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 *    ** ******* *   *** * * ** ******** ***** *   ** *     **  *  *  ** * **        *           
*    *   *      ***      *     **  ** *** *   *    *    *  ** **  *    
 * * *      ** * * *     **  **    ** * **   ** * *  ** ***   * * ***** *  * * *     * ** * ****   *** *      ****       
*  * * **  ** ****  * *   * * * ******  ***  * ** 
* *   **   **  *****   *****  ***    *  *  *   * ** *    ***  * * * * ** * ****** *   ;
   ** * **     **  ***   *   *  
*  * *  *  *  *   *  ***** *** ** 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