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