Why is the program keeping output the same value?

Question

#include<iostream>
using namespace std;

int main()
{
    double x = 0.625, E = 0.0001;
    double value[2] = { 1 / x, 0 };
    for (int count = 0; ; count++)
    {
        value[1] = ((3 / 2) * value[0]) - ((1 / 2) * x * pow(value[0], 3));
        cout << value[1] << value[0];
        value[0] = value[1];
    }

}

Why doesn't value[1] change its number, if there is the instruction that does some calculations?(the eighth line)

Yes, but I want to know about problem with the second element of the "value" array — mad_cockroach_, Jun 02 '22 at 11:27
Unrelated: You will not be happy with `cout << value[1] << value[0];`. Let's say it prints `3.141592.71828`, where does the second number starts? Is it `2.7` or `92.7` or .... ? — mch, Jun 02 '22 at 11:51

tenfour · Answer 1 · 2022-06-02T11:37:13.363

2

(3 / 2) and (1 / 2) are integral operations and do not produce fractional results. They do not produce 1.5 and 0.5 like you expect; they return 1 and 0, cancelling out half of your calculation.

Try instead with (3.0 / 2) and (1.0 / 2)

...or simply 1.5 and 0.5.

edited Jun 02 '22 at 11:37

answered Jun 02 '22 at 11:27

tenfour

36,141
15
83
142

2

`(3 / 2)` is `1`. – mch Jun 02 '22 at 11:29
And to get not integer number, I need to use number with point, like 1.5 and 0.5 – mad_cockroach_ Jun 02 '22 at 11:35

Why is the program keeping output the same value?

1 Answers1