#include <stdio.h>
#include <math.h>
#include <time.h>
 
double func(double x) {
    return x * sin(x * 0.5);
}
 
int main() {
    double b = 3.1415926;
    const int n = 10000;
    const double h = b / n;
    const double c = 0.5 * h;
 
    clock_t start, end;
    double total_time = 0.0;
 
    for (int j = 0; j < 10000; j++) {
        double s = func(b);
        double x = h;
 
        for (int i = 1; i < n; i += 2) {
            s += 2.0 * (func(x) + func(x + h));
            x += 2.0 * h;
        }
        s *= c;
    }
 
    return 0;
}

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