709. To Lower Case
Tags: ‘String’
Implement function ToLowerCase() that has a string parameter str, and returns the same string in lowercase.
Example 1:
Input: "Hello" Output: "hello"
Example 2:
Input: "here" Output: "here"
Example 3:
Input: "LOVELY" Output: "lovely"
Solution
Character in Java have int value according to ASCII table. We can do calculation on char directly.
Different of Upper case and Lower case is 32: Lower - Upper = 32;
public String toLowerCase(String str) {
String result = "";
int diff = 'a' - 'A';
for (int i = 0; i < str.length(); i++) {
char c = str.charAt(i) ;
if (c >= 'A' && c <= 'Z') { // upper case
c += diff;
}
result += c;
}
return result;
}