index = str.charAt(i) - 'A' code example

Example 1: get certain character from string java

String words = "Hi There"; //creating a string var named 'words'
char index = words.charAt(0); /* setting a variable 'index' to letter
'0' of variable 'words'. In this case, index = 'H'.*/
System.out.println(index); //print var 'index' which will print "H"

Example 2: javascript charat

/*
charAt() method
This method takes in a string and an index as input
and returns the character at that position in the specified string
*/

myString = "Hello World!";

console.log(myString.charAt(0)); // outputs "H"
console.log(myString.charAt(5)); // outputs " "
console.log(myString.charAt(8)); // outputs "r"
// If the specified index is bigger or equal to the length of the string,
// the output will be "".
console.log(myString.charAt(23)); // outputs ""