Turn while loop into math equation?

float a = someValue;
int b = someOtherValue;
int c = 0;

while (a <= -b / 2) {
    c--;
    a += b;
}
while (a >= b / 2) {
    c++;
    a -= b;
}

c = floor((a+b/2)/b)
a = a - c*b

x = (a+b/2)/b
y = (a-b/2)/b
c = (x≤0)*(ceiling(x) - 1 + (x is integer))
   +(y≥0)*(1 + floor(y))

c = (int)((a - (b / 2)) / b + 1);
a -= c * b;

c = ((int) a + b / 2 * sign(a)) / b