#include <iostream> using namespace std; const int SIZE = 100; int main() { int p[SIZE]; int n, tot, i, cn; tot = 0; cin >> n; for(i = 1; i <= n; i++) p[i] = 1; for(i = 2; i <= n; i++){ if (p[i] == 1) tot++; cn = i * 2; while (cn <= n) { p[cn] = 0; cn += i; } } cout << tot << endl; return 0; }
输入:30
输出:_________