#include <iostream>
#include "math.h"

using namespace std;

bool isPrimeNumber(int number) { //判斷是否為素數
    float sqrtOfNum = sqrt(number);
    for (int j = 2; j <= sqrtOfNum; j++) //從2到number的算術平方根迭代
        if (number / j * j == number) //判斷j是否為number的因數
            return false;
    return true;
}

void printNum(int number) { //打印出 <= number的所有質數
    int j = 0;
    for (int i = 2; i <= number; i++)
        if (isPrimeNumber(i) == true) {
            cout << ("%-5d", i) << " ";
            j++;
            if (j % 10 == 0) //每隔十個數字換行
                cout << endl;
        }
}

int main() {
    long start = time(NULL);
    cout << (bool) isPrimeNumber(29) << endl;
    printNum(1000);
    long end = time(NULL);
    cout << endl << "Time spent: " << (end - start + 1) << endl;
}
 

執行結果:

1
2 3 5 7 11 13 17 19 23 29 
31 37 41 43 47 53 59 61 67 71 
73 79 83 89 97 101 103 107 109 113 
127 131 137 139 149 151 157 163 167 173 
179 181 191 193 197 199 211 223 227 229 
233 239 241 251 257 263 269 271 277 281 
283 293 307 311 313 317 331 337 347 349 
353 359 367 373 379 383 389 397 401 409 
419 421 431 433 439 443 449 457 461 463 
467 479 487 491 499 503 509 521 523 541 
547 557 563 569 571 577 587 593 599 601 
607 613 617 619 631 641 643 647 653 659 
661 673 677 683 691 701 709 719 727 733 
739 743 751 757 761 769 773 787 797 809 
811 821 823 827 829 839 853 857 859 863 
877 881 883 887 907 911 919 929 937 941 
947 953 967 971 977 983 991 997 
Time spent: 1