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