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