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