Bad programming my old bachelors thesis

for(double i = 1; i <= n / 2; i++) {
    double x = (2 * i - 1);
    result += h * 4 / 3 * mathFunc(a + x * h);
}
for(double i = 1; i <= n / 2 - 1; i++) {
    double x = (2 * i);
    result += h * 2 / 3 * mathFunc(a + x * h);
}