C++程序计算表达式值：求和公式 (1^2 + 2^2 + ... + n^2) / n

#include #include using namespace std;

int main() { int n; cin >> n; double sum = 0; if (n > 0) { for (int i = 1; i <= n; ++i) { sum += i * i; } sum /= n; } cout << '表达式的值=' << fixed << setprecision(4) << sum << endl; return 0; }