Obtaining length from char * variable

[bob2509]

I've converted char *itemPrice to a float, but I can't seem to get the length of the char *itemPrice before I convert it in order to do some error checking to make sure all characters are numbers.

Here's the code

int PriceItemLength;
						
cout << endl << " You entered option 3" << endl << endl;
system("pause");
system("cls");
cout << endl << " Please enter a price: $"; 
cin >> itemPrice1;

PriceItemLength = itemPrice1.length();  // having problem here

while (index < PriceItemLength)
{
       if (itemPrice1[index] == '9' || itemPrice1[index] == '8' 
       || itemPrice1[index] == '7' || itemPrice1[index] == '6' 
       || itemPrice1[index] == '5' || itemPrice1[index] == '4' 
       || itemPrice1[index] == '3' || itemPrice1[index] == '2' 
       || itemPrice1[index] == '1' || itemPrice1[index] == '0'
       || itemPrice1[index] == '.') 
				
       index++;									
       else
      {
               system("cls");
               cout << endl << " Please enter a price only!";
               cout << endl << " Please enter a price: $"; 
               cin >> itemPrice1;
               index = 0; 
       }
} // ends while loop

double x; 
x = atof( itemPrice1 );	
cout << setprecision(2) << x;

I can't get the length of itemPrice1 in order to do the error checking.

bob2509

[ygfperson]

int i=0;
for (i=0;char[i];i++);

in the end i will be the length not including the null terminator

[bob2509]

makes sense. Thanks!

[Prelude]

Assuming that you've allocated enough space for itemPrice and nul terminated the string, the strlen function in <cstring> will get the length for you.

-Prelude

[Dual-Catfish]

if (itemPrice1[index] == '9' || itemPrice1[index] == '8' 
       || itemPrice1[index] == '7' || itemPrice1[index] == '6' 
       || itemPrice1[index] == '5' || itemPrice1[index] == '4' 
       || itemPrice1[index] == '3' || itemPrice1[index] == '2' 
       || itemPrice1[index] == '1' || itemPrice1[index] == '0'
       || itemPrice1[index] == '.')

God thats ugly.. how about

if ((itemPrice1[index] <= 9 && itemPrice1 >= 0) || itemPrice1 == '.')

[bob2509]

I like it... It sucks being a newbie...

[Unregistered]

This is pretty code isn't it?

	switch( itemPrice1[ index ] )
	{
	case '1':
	case '2':
	case '3':
	case '4':
	case '5':
	case '6':
	case '7':
	case '8':
	case '9':
	case '0':
	case '.':
		//blah blah blah......
	}

[Dual-Catfish]

This is pretty code isn't it?

For this particular situation... no

[Sebastiani]

Or even more simply...

if( isdigit( itemPrice1[index] ) || itemPrice1[index] == '.' )

[Sebastiani]

better yet, just clean up your code with a single function:

bool isNumber( char str[] )
{
char *s;

for( s = str; *s; s++ )

if( !isdigit(*s) && *s != '.' )
retrurn false;

return true;
}

That would let you do just:

						
cout << endl << " You entered option 3" << endl << endl;
system("pause");

do{

system("cls");
cout << endl << " Please enter a price: $"; 
cin >> itemPrice1;

if( !isNumber ( itemPrice1  ) )
 {
               system("cls");
               cout << endl << " Please enter a price only!";
               cout << endl << " Please enter a price: $"; 
               cin >> itemPrice1;
               index = 0; 
}

else break; 

} while( 1 );  //...infinate loop...

double x; 
x = atof( itemPrice1 );	
cout << setprecision(2) << x;