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