#include <iostream>
#include <vector>
    using namespace std;
 
    double voltage(double v) {
        return v;
    }
    double hdot(double h) {
        return h * 2;
    }
    double ndot(double n) {
        return n * 3;
    }
 
    typedef double(*eqpointer)(double);
 
int main() {
    vector<eqpointer> ODE = { voltage, hdot, ndot };
    int eq_num = ODE.size(); // quantity elements in ODE[]
    vector<double> midvalues(eq_num);
    for (int j = 0; j < eq_num; j++) {
        midvalues[j] = (*ODE[j])((j + 1) * 10) / 2;  // Value For Example
        printf("midvalues[%d]: %f\n", j, midvalues[j]);
    }
    return 0;
}

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