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