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