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