怀疑人生的入门题，求助

#include<iostream>
#include <cmath>
#include <algorithm>
#include <iomanip>
using namespace std;
const double pai = 3.141593;
int main() {
    int T;
    cin >> T;
    if (T == 1) {
        cout << "I love Luogu!";
    }
    else if (T == 2) {
        cout << 2 + 4 << " " << 10 - 2 - 4;
    }
    else if (T == 3) {
        cout << 3 << endl << 12 << endl << 2;
    }
    else if (T == 4) {
        double b = 500.000000 / 3.000000;
        cout << setiosflags(ios::fixed) << setprecision(3) << b;
    }
    else if (T == 5) {
        cout << (260 + 220) / (12 + 20);
    }
    else if (T == 6) {
        cout << sqrt(pow(6, 2) + pow(9, 2));
    }
    else if (T == 7) {
        cout << 100 + 10 << endl;
        cout << 110 - 20 << endl;
        cout << 90 - 90 << endl;
    }
    else if (T == 8) {
        cout << double(1.0*pai * 10.0) << endl << double(1.0*pai * 25.0) << endl << double(1.0*double(4 / 3) * pai * 125.0) << endl;
    }
    else if (T == 9) {
        cout << 2 * (2 * (2 * (1 + 1) + 1) + 1) << endl;
    }
    else if (T == 10) {
        cout << 9;
    }
    else if (T == 11) {
        cout << 1.0 * 100 / 3;
    }
    else if (T == 12) {
        cout << int('M' - 'A') + 1 << endl;
        cout << char('A' + 17);
    }
    else if (T == 13) {
        cout << (int)(pow(double(double(4 / 3) * pai * double(4 * 4 * 4 + 10 * 10 * 10)), double(1 / 3)));
    }
    else if (T == 14) {
        cout << 50;
    }
    return 0;
}

请问T8和T13为什么过不了？

话说这是小学数学题吗？这是信息学入门题吗？都快怀疑人生了QAQ