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About appending strings in C++

Started by Leiarchy9 Dec 28, 2003 at 8:47 PM 8 replies 600+ views

Original Post

Dec 28, 2003 at 8:47 PM

#include <cstdio>
#include <cstdlib>


int main( void )
{

     char Buffer[100];
     char* Name= new char[100];
     int number;
     
     
     printf( "Please Input A Number: " );
     scanf( "%s", Name );
     
     
     sprintf( Buffer, "%s", Name );
     printf( "Hi %s!!", Buffer );
     
     
     rewind( stdin );
     rewind( stdout );
     
     delete [] Name;
     
     return(EXIT_SUCCESS);
}

The sprintf() function.....is there a C++ equivalent to it? That also handles std::string? -------- "Do you believe in Ghost?"

SiCrane

Dec 28, 2003 at 8:58 PM

The classic way to append std::string objects in C++ is to use opeartor+(). e.g.:


int main() {
  std::string a("Moo");
  std::string b("cow");
  
  std::string c = a + b;
  
  std::cout << c.c_str() << std::endl;
  return 0;
}

std::string also supplies an append() member function.

For sprintf() like functionality, the common method is to use std::stringstream.

Thunder_Hawk

Dec 28, 2003 at 9:07 PM

quote:
Original post by SiCrane

std::cout << c.c_str() << std::endl;

 std::cout << c << std::endl;

will suffice...cout can handle std::string just like a C-style string.

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The Flood

Dec 28, 2003 at 9:17 PM

You can also use std::string::append()

To append a std::string or char* :

std::string mystring1, mystring2;
char* sz;

mystring1.append(mystring2);
mystring1.append(sz);

Hope this helps!!

[edited by - The Flood on December 28, 2003 10:21:42 PM]

SiCrane

Dec 28, 2003 at 9:32 PM

quote:
Original post by Thunder_Hawk
std::cout << c << std::endl;

will suffice...cout can handle std::string just like a C-style string.

Force of habit; there was a bug in one of the early STL implementations that made operator<<(std::ostream &, std::string &) leak memory.

daerid

Dec 29, 2003 at 12:11 AM

The C++ equivalent to scanf() would be either operator >> or std::getline:


#include <iostream>

using namespace std;

int main(int argc,char* argv[])
{
  string name;
  cout << "Enter Name: " << flush;
  // You could use:

  // - cin >> name;

  // but that would end the name at the

  // first whitespace character

  getline(cin,name);
  
  cout << "You entered \"" << name << "\" as your name." << endl;
}

Leiarchy9

Dec 29, 2003 at 12:55 AM

daerid? What is your point?

Leiarchy9

Dec 30, 2003 at 11:26 PM

bump

--------
"Do you believe in Ghost?"

invective

Dec 31, 2003 at 12:57 AM

quote:
Original post by Leiarchy9
The sprintf() function.....is there a C++ equivalent to it? That also handles std::string?

The C++ equivalent to sprintf, which incendentally is a potentially horribly evil function because it does not check the size of your buffer and can easily overflow it, is std::ostringstream. std::ostringstream is similar to std::cout, as the both inherit from std::ostream. It is far less evil than sprintf, because it manages its own memory.

see here:
http://www.cplusplus.com/ref/

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