import java.util.HashMap;
import java.util.Map;

public class SymbolTable {
	
	private Map<String, String> table;
	
	public SymbolTable() {
		table = new HashMap<String, String>();
	}
	
	public String lookupVal(String key) {
		return table.get(key);
	}
	
	public String storeVal(String key, String val) {
		return table.put(key, val);
	}
	
	public boolean isDefined(String key) {
		return table.containsKey(key);
	}
	
}
