Initial Commit

Corgi/MemTable.java

@@ -0,0 +1,75 @@
+/*
+  store variable names with stored value
+*/
+
+import java.util.ArrayList;
+
+public class MemTable {
+
+  private ArrayList<String> names;
+  private ArrayList<Double> values;
+
+  public MemTable() {
+    names = new ArrayList<String>();
+    values = new ArrayList<Double>();
+  }
+
+  public String toString() {
+    String s = "----\n";
+    for( int k=0; k<names.size(); k++ ) {
+      s += names.get(k) + " " + values.get(k) + "\n";
+    }
+    return s;
+  }
+
+  public int size() {
+    return names.size();
+  }
+
+  // store value for name, adding name if not already
+  // there
+  public void store( String name, double value ) {
+
+     int loc = findName( name );
+   
+     if ( loc < 0 ) {// add new pair
+        names.add( name );
+        values.add( value );
+     }
+     else {// change value for existing pair
+        values.set( loc, value );
+     } 
+
+  }// store
+
+  // retrieve value for given name
+  public double retrieve( String name ) {
+
+     int loc = findName( name );
+
+     if ( loc >= 0 ) {// add new pair
+        return values.get( loc );
+     }
+     else {
+        System.out.println("variable [" + name + "] not found");
+        System.exit(1);
+        return 0;
+     }
+  
+  }// retrieve
+
+  // return index of name in names, or -1 if
+  // not found
+  private int findName( String name ) {
+     // locate name
+     int loc = -1;
+     for (int k=0; k<names.size() && loc<0; k++) {
+        if ( names.get(k).equals(name) ) {
+           loc = k;
+        }
+     }
+
+     return loc;
+  }// findName
+
+}