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