check letters

gistfile1.txt

Scanner in = new Scanner(System.in);
String input = "";
int nonLetters;
boolean hasNonLetters = false;
while(!hasNonLetters) {
	nonLetters = 0;
	System.out.println("Please enter a valid input");
	input = in.next();
	for (int i = 0; i < input.length(); i++) {
	
//You should check out the ascii table here: https://www.cs.cmu.edu/~pattis/15-1XX/common/handouts/ascii.html
//to see exactly what you want to check for. The logic that checks the value is in the if statement below.
//that "(int)" part casts the input character to an integer and that integer is the ascii value.

		if ((int) input.charAt(i) < 64) { 
		  nonLetters++;
		}
	}
	if (!(nonLetters > 0)) {
		hasNonLetters = true;
	}
}
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