add positiv_zero in output

src/utils/math.c

@@ -31,6 +31,13 @@ const s_polynom *get_term_of_power(const s_polynom *polynom, int power)
     return &polynom[i];
 }
 
+double positiv_zero(double num)
+{
+    if (is_nearly_equal_zero(num))
+        return 0.0;
+    return num;
+}
+
 bool has_decimal_part(double num)
 {
     return (!is_nearly_equal(num, (int)num));