class ArrayIntro extends Object120 {
    
    /** return the sum of all numbers in `nums`.
     */
    static double sumOfArray( double[] nums ) {
        double sumSoFar = 0;
        int i = 0;
        while ( i < length(nums)) {
            sumSoFar = sumSoFar + nums[i];
            i += 1;
        }
        return sumSoFar;
    }
    
    

    static double[] cumulate( double[] data ) {
        double[] answerSoFar;
        answerSoFar = new double[ length(data) ]; 

        double sumSoFar;
        sumSoFar = 0.0;

        int i = 0;
        while ( i < length(data)) {
            sumSoFar = sumSoFar + data[i];
            answerSoFar[i] = sumSoFar;
            i += 1;
        }
        return answerSoFar;
    }
    

    /** return the avg of all numbers in `nums`.
     * pre-condition: length(nums) != 0
     */
    static double avgOfArray( double[] nums ) {
        return sumOfArray(nums) / length(nums);
    }
    
    
    
    
    
    public static void main( String[] args ) {
        double[] rainfall;
        rainfall = new double[]{3.7, 2.1, 4.5, 99.7, 0.0, 4.0};
        
        assertEquals( 0.0, sumOfArray(new double[]{}) );
        assertEquals( 5.0, sumOfArray(new double[]{5}) );
        assertEquals( 7.5, sumOfArray(new double[]{5, 2.5}) );
        
        assertEquals( 5.0, avgOfArray(new double[]{5}) );
        assertEquals( 1.25, avgOfArray(new double[]{0, 2.5}) );
       
        assertEquals( new double[]{3.7, 5.8, 10.3, 110.0, 110.0, 114.0 },
                      cumulate(rainfall) );
        System.out.println( "The total rainfall is " + sumOfArray(rainfall) );
        
        rainfall = new double[1000];
    }
    
}