Summation of primes Problem 10 The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below two million. Answer: 142913828922 翻译 质数的和 问题 10 10以内所有质数的和是: 2 + 3 + 5 + 7 = 17. 求2000000以内所有质数的和。 答案: 142913828922 解法一: #include <stdio.h> #include <math.h> bool isPrime(long num) { int _sqrt = (long)sqrt(num); if (num == 2 || num == 3) { return true; } for (int i = 2; i <= _sqrt; i++ ) { if (num % i == 0) { return false; } } return true; } int main(int argc, char *argv[]) { long long result = 0; long maxNum = 2000000; int _count = 1; for (long i = 2; i<maxNum; i++) { if (isPrime(i)) { result += i; _count++; } } printf("result is %I64d \n",result); return 0; }