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