char *

[Carmen Sei]

why the following compile is OK

but will crash when execute?

the problem seem to in -
convertToUppercase( phrase );

==========
// Converting lowercase letters to uppercase letters
// using a non-constant pointer to non-constant data.
#include <iostream>
using std::cout;
using std::endl;

#include <cctype// prototypes for islower and toupper
using std::islower;
using std::toupper;

void convertToUppercase( char * );

int main()
{
//char phrase[] = "characters and $32.98";

char * phrase = "characters and $32.98";

convertToUppercase( phrase );

return 0; // indicates successful termination
} // end main

// convert string to uppercase letters
void convertToUppercase( char *sPtr )
{
while ( *sPtr != '\0' ) // loop while current character is not '\0'
{
if ( islower( *sPtr ) ) // if character is lowercase,
*sPtr = toupper( *sPtr ); // convert to uppercase

sPtr++; // move sPtr to next character in string
} // end while
} // end function convertToUppercase

[Carmen Sei]

to declare a string like

"abcd"

I should never use char * right?

i should always use const char * for string declare?

or i should always use char[]?

[Sharad]

"Carmen Sei" <fa**********@yahoo.comwrote in message

why the following compile is OK

but will crash when execute?

the problem seem to in -
convertToUppercase( phrase );

==========
// Converting lowercase letters to uppercase letters
// using a non-constant pointer to non-constant data.
#include <iostream>
using std::cout;
using std::endl;

#include <cctype// prototypes for islower and toupper
using std::islower;
using std::toupper;

void convertToUppercase( char * );

int main()
{
//char phrase[] = "characters and $32.98";

char * phrase = "characters and $32.98";

convertToUppercase( phrase );

return 0; // indicates successful termination
} // end main

// convert string to uppercase letters
void convertToUppercase( char *sPtr )
{
while ( *sPtr != '\0' ) // loop while current character is not '\0'
{
if ( islower( *sPtr ) ) // if character is lowercase,
*sPtr = toupper( *sPtr ); // convert to uppercase

sPtr++; // move sPtr to next character in string
} // end while
} // end function convertToUppercase

Check a recent thread with subject "strcat" on this NG. In short, what are
you trying to modify and is it modifiable?

Sharad
P.S. - Also, does it work when you make phrase an array (the commented code)
and why?