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