#include <iostream.h>
#include <iomanip.h>
#include "math.h"
void main(void) {
int a1[51] = {0};
int i, j, t, t2, n = 50;
for (i = 2; i <= sqrt(n); i++)
if (a1[i] == 0) {
t2 = n / i;
for (j = 2; j <= t2; j++) a1[i * j] = 1;
}
t = 0;
for (i = 2; i <= n; i++)
if (a1[i] == 0) {
cout << setw(4) << i;
t++;
if (t % 10 == 0) cout << endl;
}
cout << endl;
}
输出：1
