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