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