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