public char findCenter(String S) {
    int center = S.length() / 2 + 1;
    char a = S.charAt(center);
    return a;
}

Main.java:1: error: class, interface, or enum expected
public char findCenter(String S){
       ^
Main.java:3: error: class, interface, or enum expected
		char a=S.charAt(center);
		^
Main.java:4: error: class, interface, or enum expected
		return a;
		^
Main.java:5: error: class, interface, or enum expected
}
^
4 errors