好的,所以我创建的这个函数使用 Eratosthenes 算法来计算所有素数 <= n。该函数在参数中存储素数和素数。
当函数退出时,素数应该指向一块动态分配的内存,其中包含所有素数<= num。*count 将有素数的计数。
这是我的函数 getPrimes:
void getPrimes(int usernum, int* count, int** array){
(*count) = (usernum - 1);
int sieve[usernum-1], primenums = 0, index, fillnum, multiple;
//Fills the array with the numbers up to the user's ending number, usernum.
for(index = 0, fillnum = 2; fillnum <= usernum; index++, fillnum++){
sieve[index] = fillnum;
}
/*Starts crossing out non prime numbers starting with 2 because 1 is not a prime. It then deletes all of those multiples and
moves on to the next number that isnt crossed out, which is a prime. */
for (; primenums < sqrt(usernum); primenums++){ //Walks through the array.
if (sieve[primenums] != 0){ //Check's if that number is 0 which means it's crossed out
for (multiple = (sieve[primenums]); multiple < usernum; multiple += sieve[primenums]){ //If it is not crossed out it starts deleting its multiples.
//Crossing multiples out and decrements count to move to next number
sieve[multiple + primenums] = 0;
--(*count);
}
}
}
int k;
for (k = 0; k < usernum; k++)
if (sieve[k] != 0){
printf(" %d", sieve[k]);
}
printf(" ");
array = malloc(sizeof(int) * (usernum + 1));
assert(array);
(*array) = sieve;
}
我的函数在这里编译得很好,但是我注意到当我尝试从 101 开始的更大数字时出现分段错误。有谁看到我的代码在哪里产生分段错误?