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