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