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