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Acmlm's Board - I2 Archive - Programming - Testing if a value is a number or not... (c++) | |
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Weasel
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Since: 03-15-04
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Posted on 03-22-04 08:30 AM Link | Quote
OK, here's a code fragment:

double variable;
cin >> variable;

Gee, that was a lot, eh?

Let's say I have a stupid user that, instead of entering a real number into that fine variable, he enters a character, like - or \ or something stupid.

I want to have the program stop if this happens. I need some sort of test to see if the value entered is a number and not some other type like a string or character.

Any ideas on how to do this?
Cellar Dweller

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Posted on 03-22-04 09:56 AM Link | Quote
if you don't mind falling back on C library functions you could input a string and process it with strtod(). The code should look something like this:

char *endptr;

double_var = strtod(input_string_ptr, &endptr);
if (endptr == input_string_ptr) {
punish_user_severely();
}
Kenny3900
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Posted on 03-22-04 02:15 PM Link | Quote
I think if the user is stupid enough to enter a non-numerical data (), an error will be given out.

So use try/catch may help.
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