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