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