KB168376 - PRB: STL string Class insert Function Does Not Work as Expected

Article ID: 168376

Article Last Modified on 12/2/2003

The Standard C++ Library, when used with:
- Microsoft Visual C++ 4.2 Enterprise Edition
- Microsoft Visual C++ 4.2 Professional Edition
- Microsoft Visual C++ 5.0 Enterprise Edition
- Microsoft Visual C++ 5.0 Professional Edition
- Microsoft Visual C++ 6.0 Enterprise Edition
- Microsoft Visual C++ 6.0 Professional Edition
- Microsoft Visual C++ 6.0 Standard Edition

This article was previously published under Q168376

SYMPTOMS

The string::insert member function does not work as expected. This is because the same string object is used for modification and input. Many data manipulation routines do not check for overlapping or identical arguments, causing unexpected results.

RESOLUTION

Create a temporary copy of the string as shown below:

s.insert(0, string("b"), 1);

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce Behavior

#include <iostream>
#include <string>
using namespace std ;

void f1()
 {
  string s ("abc");
  s.insert (0, s, 1, 1);
  cout << "s (should be 'babc'): " << s << endl << endl;
 }

int main ()
  {
    f1();// prints "aabc" instead of "babc"
    return 0 ;
  }

Keywords: kbprogramming kbprb KB168376