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