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()
{
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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