How to find out no. digits present in a alphanumeric string entered by a user?

Answer 1

Use Regular Expressions. Because i dont know in which language you are code i cant search for an example in your language.

but here is a article what are regulr expressions: https://en.wikipedia.org/wiki/Regular_expression

a small java example but its hard to understand if you never heard of regexp or dont use java:

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RegexMatches {

public static void main( String args[] ) {
// String to be scanned to find the pattern.
String line = "This order was placed for QT3000! OK?";
String pattern = "(.*)(\\d+)(.*)";

// Create a Pattern object
Pattern r = Pattern.compile(pattern);

// Now create matcher object.
Matcher m = r.matcher(line);
if (m.find( )) {
System.out.println("Found value: " + m.group(0) );
System.out.println("Found value: " + m.group(1) );
System.out.println("Found value: " + m.group(2) );
}else {
System.out.println("NO MATCH");
}
}
}
This will produce the following result −

Output
Found value: This order was placed for QT3000! OK?
Found value: This order was placed for QT300
Found value: 0

Answer 2

I want it to be in c++. I don't know java. Yeah i should have mentioned it before!!
😀