dev-cpp-users

[Dev-C++] RE : [c-prog] what's wrong with the code

[Dawood V. <da...@ku...>]

Subject: RE : [c-prog] what's wrong with the code

I tried  "using namespace std;" it still gives me error.
I tried:  string p(1,ch);  But it does not serve the purpose of the 
code,  Basically, I want to enter one character at the back of the string 
at one time.
Lastly, it simply does not compile:  below is the same code, I produce 
again, with the type of compile time error it gives.  The details about the 
errors are in the comments of the code just below the line which is 
responsible for the error.  I need two things.  Explanation and alternative.


#include <iostream.h>
#include <stdlib.h>
#include <string>


int main()
{
   char ch = 'z';
   string p = ch;
   /* for the above line the following is the error it gives me :
  conversion from `char' to non-scalar type 
`basic_string<char,string_char_traits<char>,__default_alloc_template<false,0>  
 >' requested
  */
   p.push_back(ch);
  /* for the above line the following is the error it gives me :
  no matching function for call to 
`basic_string<char,string_char_traits<char>,__default_alloc_template<false,0>  
 >::push_back (char &)'
*/
       system("PAUSE");
       return 0;
}

Re: [Dev-C++] RE : [c-prog] what's wrong with the code

[Daniel K. O. <dan...@ya...>]

Dawood Vora wrote:

> int main()
> {
>   char ch = 'z';
>   string p = ch;
>   /* for the above line the following is the error it gives me :
>  conversion from `char' to non-scalar type 
> `basic_string<char,string_char_traits<char>,__default_alloc_template<false,0>  
> >' requested
>  */ 


Long story short: a string can't be initialized from a 'char' like this.
 From The Man himself (TC++PL 3rd, 20.3.4):

---
void f(char *p, vector<char>& v)
{
    string s0;               // ok: empty
    string s00 = "";      //  ok: empty too

    string s1 = 'a';       // error
    string s2 = 7;         // error
    string s3 (7);         // error
    srtring s4(7, 'a');   // OK: s4 = "aaaaaaa"

    string s5 = "Frodo";   // OK: copy of "Frodo"
    string s6 = s5;            // OK: copy of s5

    string s7(s5, 3, 2);      // OK: s7 = s5[3] and s5[4] = "do"
    string s8(p+7, 3);      // OK: p[7], p[8] and p[9]
    string s9(p, 7, 3);      // OK: string(string(p), 7, 3)
    string s10(v.begin(), v.end());   // OK: copy all chars from v
}
---



>   p.push_back(ch);
>  /* for the above line the following is the error it gives me :
>  no matching function for call to 
> `basic_string<char,string_char_traits<char>,__default_alloc_template<false,0>  
> >::push_back (char &)'
> */


Try:
---
    p+=ch;
---





Daniel K. O.

RE: [Dev-C++] RE : [c-prog] what's wrong with the code

[Ioannis V. <iv...@em...>]

> -----Original Message-----
> From: dev...@li... 
> [mailto:dev...@li...] On Behalf 
> Of Dawood Vora
> Sent: Tuesday, August 12, 2003 4:21 AM
> To: Dev C++
> Subject: [Dev-C++] RE : [c-prog] what's wrong with the code
> 
> 
> Subject: RE : [c-prog] what's wrong with the code
> 
> I tried  "using namespace std;" it still gives me error.

> #include <iostream.h>


#include <iostream>


But you do not use any facilities of <iostream> in your code.


> #include <stdlib.h>

Better: #include <cstdlib>



> #include <string>
> 
> 
> int main()
> {

   using namespace std;

>    char ch = 'z';
>    string p = ch;
>    /* for the above line the following is the error it gives me :
>   conversion from `char' to non-scalar type 
> `basic_string<char,string_char_traits<char>,__default_alloc_te
> mplate<false,0>  
>  >' requested
>   */


The above line is wrong. There is no string constructor taking a char as an
argument.


So your code becomes:


#include <cstdlib>
#include <string>


int main()
{
   using namespace std;

   char ch = 'z';
   string p;

   p.push_back(ch);
   system("PAUSE");

   return 0;
}






Ioannis Vranos
 
* Programming pages: http://www.noicys.freeurl.com
* Alternative URL 1: http://run.to/noicys
* Alternative URL 2: http://www.noicys.cjb.net

RE: [Dev-C++] RE : [c-prog] what's wrong with the code

[<a_g...@ya...>]

string p =ch; file://does not make much sense to me!!!

Ioannis Vranos <iv...@em...> wrote:> -----Original Message-----
> From: dev...@li... 
> [mailto:dev...@li...] On Behalf 
> Of Dawood Vora
> Sent: Tuesday, August 12, 2003 4:21 AM
> To: Dev C++
> Subject: [Dev-C++] RE : [c-prog] what's wrong with the code
> 
> 
> Subject: RE : [c-prog] what's wrong with the code
> 
> I tried "using namespace std;" it still gives me error.

> #include 


#include 


But you do not use any facilities of in your code.


> #include 

Better: #include 



> #include 
> 
> 
> int main()
> {

using namespace std;

> char ch = 'z';
> string p = ch;
> /* for the above line the following is the error it gives me :
> conversion from `char' to non-scalar type 
> `basic_string,__default_alloc_te
> mplate 
> >' requested
> */


The above line is wrong. There is no string constructor taking a char as an
argument.


So your code becomes:


#include 
#include 


int main()
{
using namespace std;

char ch = 'z';
string p;

p.push_back(ch);
system("PAUSE");

return 0;
}






Ioannis Vranos

* Programming pages: http://www.noicys.freeurl.com
* Alternative URL 1: http://run.to/noicys
* Alternative URL 2: http://www.noicys.cjb.net




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   Avik Ghose
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