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