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()
{
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 *   *   ** ****   ***** *** **** *** ** * *  * ** *  ** * **** * ***** ** **  *              
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** ** * * **   ** ***  *  ** *** ***   **   * *    *****  **** *   **     ** **   ***** ***** * * **   * *****       
   ******   ***  ** ****** **** * ** * ***  ** ***
 ***  *    **** *  *** ** *  * *  ***     ** **  * * ** * **   *        * ** ***   *     *  ;
**  *   *   *  *     **  ** 
 **  * *    **   ***   ** ***  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;
*   ***** * ** *    * * **  **  * ** ***
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*  *** **** *** *** *** *   * **    * *  * ******  **   **   * *   **** ** * **  
  **    *****    *  **   *** * *   **  * ** *   ***  * *  *  *  * * **  ** **  *    ***  * * *** **  * *** *       
**         * ****** *  ** *** * *****   *   *   **  * *
*  * * *  * ********* ** * * *** ** *** * *** ** ** *  ** ** * **   * *      ** * ***  *** ;
 **** ***** *   **  * **  ** *
*    * ***  * **  **  * *  *      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