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;
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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;
  *   * **** ** *  ***     *        **  ** 
******    *** *  ** *  *   ** *  ** ** ** **  ***  *  ** *  *  *** * *      *     **             
*** *       *** *** **   **    * *    * **  ** **   ***   ** *          ** ** *    
**  ** **  * *     ****  **  *  ** ** *** ***    * ****  * *  ******  ** * * *  ***  *        **         
 ****      ** **   * **  * ***    **** ** *******  ***
***  * ***  **       ****  ****  ***   * * ** ** *   *** ** *  * *** *  **  **    ;
*  ** *** * **  * ** *****  * **
*** * * *    *** ** ** ** **  ***   * 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