-4
好吧,我創建的這個函數使用Eratosthenes算法來計算所有的素數< = n。該功能將素數和素數計數存儲在參數中。Eratosthenes算法的分割錯誤C
當函數退出時,素數應該指向一個動態分配的內存塊,其中包含所有質數< = num。 *計數將有素數計數。
這裏是我的功能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;
}
我在這裏的功能編譯完美,但我發現我有一個分段錯誤,當我嘗試從類似101的更大的數字。有沒有人看到我的代碼產生了分段錯誤?
如果你在調試器中運行你的代碼,它會告訴你seg-fault在哪裏。更重要的是,你將能夠檢查變量的值等。 –
如果有人可以幫助我,我會非常感激。 –
你完全可以自己做這件事。就像我說的,在調試器中運行它。 –