public class MyClass {
public static String convert_part_to_lowercase(String s, int idx) {
if (idx < 0 || idx > s.length()) return s;
String tmp = "";
for (int i = 0; i < s.length(); i++) {
if (i >= idx && (s.charAt(i) >= 65 && s.charAt(i) <= 90)) {
char ch = s.charAt(i);
tmp += Character.toLowerCase(ch);
}
else {
tmp += s.charAt(i);
}
}
return tmp;
}
public static void main(String args[]) {
String s = "JAVA PROGRAMMING";
s = convert_part_to_lowercase(s, 3);
System.out.println(s);
}
}
/*
run:
JAVa programming
*/