Chapter 1: find the algebraic sum of odd factors, find the same decimal sum s (D, n), simplify the same code decimal sum s (D, n), expand the same code decimal sum s (D, n)

// Find the algebraic sum of odd factors 
int main()
{
    
	int d, m, n;
    long s;
    printf(" please enter an integer n:");
    scanf("%d",&n);
    s = 0;
    for(m = 1; m <= n; m++)
    {
    
        if(m % 2 > 0) s = s + m;
        else
        {
    
            d = m;
            while(d % 2 == 0) d = d / 2;
            s = s - d;
        }

    }
    printf(" s(%d) = %ld\n", n, s);
    return 0;
}

The results verify that ：

// Do you agree? Decimal sum s(d, n)
int main()
{
    
	int d, j, n;
	double t, s;
	printf("  please enter an integer d, n:");
	scanf("%d, %d", &d, &n);
	t = s = 0;
	for (j = 1; j < n; j++)
	{
    

		t = t / 10 + (double)d / 10;
		s += t;
	}
	printf(" S(%d, %d) = %.8f\n", d, n, s);
	return 0;
}

The results verify that ：

// Simplified decimal sum of the same code s(d, n)
int main()
{
    
	int d, n;
	double s;
	printf("  please enter an integer d, n");
	scanf("%d,%d", &d, &n);
	s = (n - 0.111111111) * d / 9;
	printf(" s(%d, %d) = %.8f\n", d, n, s);
	return 0;
	
}

The results verify that ：

// Expand the decimal sum of the same code s（d, n）
int main()
{
    
    int a, b, d, j, n;
    double t, s;
    printf("  please enter an integer d, n; ");
    scanf("%d, %d", &d, &n);
    a = d;
    b = 1;
    while (a > 0)
    {
    
        b = b * 10;
        a = a / 10;
    }
    t = s = 0;
    for (j = 1; j <= n; j++)
    {
    
        t = t / b + (double)d / b;
        s += t;

    }
    printf(" s(%d, %d) = %.8f\n", d, n, s);
    return 0;
	
}

result ：