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Let's say I want to look at the character at position 10 in a string s.
s.at(10);
What would be the easiest way to know if this is a number?
449
Using built-in method isdigit(), each character of string is checked. If the string character is a number, it will print that string contains int. If string contains character or alphabet, it will print that string does not contain int.
To check if a string is an integer or a float:Use the str. isdigit() method to check if every character in the string is a digit. If the method returns True , the string is an integer.
If the float number only has '. 0' after it then it converts it into a integer. while CorrectNumber == False: try: Number = float(NumberString) - 0 print (Number) except: print ("Error! Not a number!")
Use isdigit
std::string s("mystring is the best");
if ( isdigit(s.at(10)) ){
//the char at position 10 is a digit
}
You will need
#include <ctype.h>
to ensure isdigit is available regardless of implementation of the standard library.
52
The other answers assume you only care about the following characters: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. If you are writing software that might operate on locales that use other numeral systems, then you'll want to use the newer std::isdigit located in <locale>: http://www.cplusplus.com/reference/std/locale/isdigit/
Then you could recognize the following digits as digits: ४, ੬, ൦, ௫, ๓, ໒
39
The following will tell you:
isdigit( s.at( 10 ) )
will resolve to 'true' if the character at position 10 is a digit.
You'll need to include < ctype >.
21
Another way is to check the ASCII value of that character
if ( s.at(10) >= '0' && s.at(10) <= '9' )
// it's a digit
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