public class ExtractFloatDigits {
/**
extractFloatDigits
-------------------
Scans the input string and extracts the digits before and after
the decimal point of the first floating‑point number found.
Steps:
1. Find the first digit.
2. Collect digits until a decimal point.
3. After '.', collect digits again.
4. Stop when a non‑digit is encountered.
This approach avoids regex overhead and uses efficient
character scanning.
*/
public static void extractFloatDigits(String s,
StringBuilder before,
StringBuilder after) {
before.setLength(0);
after.setLength(0);
int i = 0;
int n = s.length();
// Step 1: Find the first digit
while (i < n && !Character.isDigit(s.charAt(i))) {
i++;
}
// Step 2: Collect digits before the decimal point
while (i < n && Character.isDigit(s.charAt(i))) {
before.append(s.charAt(i));
i++;
}
// Step 3: Check for decimal point
if (i < n && s.charAt(i) == '.') {
i++; // skip '.'
// Step 4: Collect digits after the decimal point
while (i < n && Character.isDigit(s.charAt(i))) {
after.append(s.charAt(i));
i++;
}
}
}
public static void main(String[] args) {
// Example input string containing many words and one float
String s = "c/c++ c#893725.1046java python";
StringBuilder before = new StringBuilder();
StringBuilder after = new StringBuilder();
extractFloatDigits(s, before, after);
System.out.println("Before decimal: " + before);
System.out.println("After decimal: " + after);
}
}
/*
run:
Before decimal: 893725
After decimal: 1046
*/
