88 lines
2.2 KiB
Plaintext
Executable File
88 lines
2.2 KiB
Plaintext
Executable File
// ask this node to execute itself
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// (for nodes that don't return a value)
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public void execute() {
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if ( kind.equals("stmts") ) {
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// insert code here for Exercise 15
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}
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else if ( kind.equals("prtstr") ) {
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System.out.print( info );
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}
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else if ( kind.equals("prtexp") ) {
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// insert code here for Exercise 15
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}
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else if ( kind.equals("nl") ) {
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System.out.print( "\n" );
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}
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else if ( kind.equals("sto") ) {
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// insert code here for Exercise 15
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}
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else {
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error("Unknown kind of node [" + kind + "]");
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}
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}// execute
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// compute and return value produced by this node
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public double evaluate() {
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if ( kind.equals("num") ) {
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return Double.parseDouble( info );
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}
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else if ( kind.equals("var") ) {
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// insert code here for Exercise 15
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}
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else if ( kind.equals("+") || kind.equals("-") ) {
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// insert code here for Exercise 15
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}
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else if ( kind.equals("*") || kind.equals("/") ) {
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// insert code here for Exercise 15
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}
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else if ( kind.equals("input") ) {
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return keys.nextDouble();
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}
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else if ( kind.equals("sqrt") || kind.equals("cos") ||
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kind.equals("sin") || kind.equals("atan")
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) {
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double value = first.evaluate();
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if ( kind.equals("sqrt") )
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return Math.sqrt(value);
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else if ( kind.equals("cos") )
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return Math.cos( Math.toRadians( value ) );
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else if ( kind.equals("sin") )
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return Math.sin( Math.toRadians( value ) );
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else if ( kind.equals("atan") )
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return Math.toDegrees( Math.atan( value ) );
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else {
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error("unknown function name [" + kind + "]");
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return 0;
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}
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}
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else if ( kind.equals("pow") ) {
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// insert code here for Exercise 15
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}
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else if ( kind.equals("opp") ) {
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// insert code here for Exercise 15
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}
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else {
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error("Unknown node kind [" + kind + "]");
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return 0;
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}
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}// evaluate
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