'BEGIN'
    'COMMENT' This is a simple example of Jensen's device;

    'COMMENT' This takes the sum of expr from lo to hi, inclusive.
        The variable index is incremented through the range.;

    'REAL' 'PROCEDURE' SUM(LO, HI, INDEX, EXPR);
        'VALUE' LO, HI;
        'INTEGER' LO, HI, INDEX;
        'REAL' EXPR;
        'BEGIN'
            'REAL' ACCUM;

            'COMMENT' initialize accum to zero and add the terms.;
            ACCUM := 0.0;
            'FOR' INDEX := LO 'STEP' 1 'UNTIL' HI 'DO' 'BEGIN'
                ACCUM := ACCUM + EXPR
            'END';

            SUM := ACCUM
        'END';

    'BEGIN'
        'COMMENT' Sum of integers, 1 to 20.;
        'INTEGER' I;
        OUTREAL(1, SUM(1, 20, I, I));
        OUTSTRING(1, "\n");
    'END';

    'BEGIN'
        'COMMENT' sum of 10 die rolls;
        'INTEGER' I;
        OUTREAL(1, SUM(1, 10, I, RAND 'MOD' 6));
        OUTSTRING(1, "\n");
    'END';
	
    'BEGIN'
        'comment; mean and variance;
        'REAL' 'ARRAY' DATA[10];
        'INTEGER' I;
        'REAL' MEAN, SUMD, SUMSQ;
        'FOR' I:=1 'STEP' 1 'UNTIL' 10 'DO'
            READREAL(2, DATA[I]);
        SUMD = SUM(1, 10, I, DATA[I]);
        SUMSQ = SUM(1, 10, I, DATA[I]*DATA[I]);
        OUTSTRING(1, "Mean is: ");
        MEAN = SUMD / 10.0;
        OUTREAL(1, MEAN );
        OUTSTRING(1, "Variance is :");
        OUTREAL(1, SUMSQ / 10.0 - MEAN * MEAN);
    'END'
'END'