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