fn main() {
    let arr: Vec<u64> = vec![1;100];
    let iter_count: u64 = 10000000000;

    let sum_fns = [sum_array1, sum_array2, sum_array3];

    //let mut total_sum: u64 = 0;
    for sum_array_fn in &sum_fns {
        let t = std::time::Instant::now();
        for _ in 0..iter_count {
            sum_array_fn(&arr[..]);
            //total_sum += sum_array_fn(&arr[..]);
        }
        println!("{}", t.elapsed().as_millis());
    }
    //println!("total_sum: {}", total_sum);
}



fn sum_array1(array: &[u64]) -> u64 {
    assert!(array.len() == 100);
    array[0] + array[1] + array[2] + array[3] + array[4] + array[5] + array[6] + array[7] + array[8] + array[9] + array[10] + array[11] + array[12] + array[13] + array[14] + array[15] + array[16] + array[17] + array[18] + array[19] + array[20] + array[21] + array[22] + array[23] + array[24] + array[25] + array[26] + array[27] + array[28] + array[29] + array[30] + array[31] + array[32] + array[33] + array[34] + array[35] + array[36] + array[37] + array[38] + array[39] + array[40] + array[41] + array[42] + array[43] + array[44] + array[45] + array[46] + array[47] + array[48] + array[49] + array[50] + array[51] + array[52] + array[53] + array[54] + array[55] + array[56] + array[57] + array[58] + array[59] + array[60] + array[61] + array[62] + array[63] + array[64] + array[65] + array[66] + array[67] + array[68] + array[69] + array[70] + array[71] + array[72] + array[73] + array[74] + array[75] + array[76] + array[77] + array[78] + array[79] + array[80] + array[81] + array[82] + array[83] + array[84] + array[85] + array[86] + array[87] + array[88] + array[89] + array[90] + array[91] + array[92] + array[93] + array[94] + array[95] + array[96] + array[97] + array[98] + array[99]
}

fn sum_array2(array: &[u64]) -> u64 {
    assert!(array.len() == 100);
    let mut sum = 0;
    for v in array.iter() {
        sum += v;
    }
    sum
}

fn sum_array3(array: &[u64]) -> u64 {
    assert!(array.len() == 100);
    array.iter().sum()
}