enter and isspace

[Simonbo]

I've begun reading a bit about c type string functions and I've come across this strange behavior in my code:

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

bool numFormCheck(char[], int);

int main() {
	const int SIZE = 8;
	//Customer number:
	char custNum[SIZE];
	cout << "Enter a customer code in the format ";
	cout << "\"LLLNNNN\" (L for Letter, N for Number)\n";
	cin.getline(custNum, SIZE);
	if (numFormCheck(custNum, SIZE)) { cout << "This code is in the correct format\n"; }
	else { cout << "This code is in the wrong format\n"; }
	return 0;
}

bool numFormCheck(char custNum[], int size) {
	for (int i = 0; i < 3; ++i) {
		if (!isalpha(custNum[i])) return false;
	}
	for (int i = 3; i < size-1; ++i) {
		if (!isdigit(custNum[i])) return false;
	}
	if (!isspace(custNum[size-1])) { return false; }
	return true;}

the isspace() function I've used in the line before the last line is not working as I expect. For example I give this input "mbn1484[enter]" but isspace believes I've not entered any whitespace characters! and returns false.

[Peter87]

The newline character is not part of the string.
custNum[size-1] refers to the null character that marks the end of the string.

'm', 'b', 'n', '1', '4', '8', '4', '\0'
                                    ^
                                    |
                                    custNum[size-1]

[Simonbo]

Thank you very much. This has solved my problem. Is this part of the Cplusplus.com reference referring to the same thing? That the newline character that I entered was discarded (and then a null character was replaced with it)?

If the delimiter is found, it is extracted and discarded (i.e. it is not stored and the next input operation will begin after it).

[Peter87]

The reference page that you quoted is for the std::getline function which is not exactly the same as the getline member function that you're using.

http://www.cplusplus.com/reference/istream/istream/getline/

The delimiting character is the newline character ('\n') for the first form, and delim for the second: when found in the input sequence, it is extracted from the input sequence, but discarded and not written to s.

[...]

A null character ('\0') is automatically appended to the written sequence if n is greater than zero, even if an empty string is extracted.