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