How can I check if a string contain only floating point or number?

Question

I have to do error handling for my project and I have to check if the string contains only floating point or integer, or may be check if the string don't contains any letters or special characters. Thanks.

Answer 1

Use a regex pattern, for example, like this

(-)?\d+(.\d+)?

and check every string input against it like so

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

int main()
{
string str = "";
cout << "Input string: ";
getline(cin, str);

regex numeric("(-)?\\d+(.\\d+)?");
cout << (regex_match(str, numeric) ? str : "Invalid string!") << endl;
}

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https://www.debuggex.com/r/pW15xmR1x-5E73og

Answer 2

C++ Soldier (Babak) Nice! Finally... a fellow regexer 🤓!

Answer 3

Thanks you, I go for it!