c语言随机生成带符号的int并填充数组，检查是否有重复，挂在32768

首先，有一点背景。我是Compsci的电气工程专业的学生，​​我几乎完全是自学成才，几乎没有经过严格的编程培训，因此下面的代码中可能存在一些不“标准”的内容。

这个小程序只是一个实用程序，用于生成任意大小的数据文件，该文件填充有随机生成的带符号的int值，以用作分配的输入。我已经完成任务，并且工作正常。这是一个关于这个程序中发生的奇怪事情的问题，对我而言，这只是在我添加代码部分以检查重复项时才开始发生的。以前，它只是将整数直接转储到一个文件中，每行一个。然后，我意识到这并不是教授数据的严格格式化方式，因此我进行了更改以防止重复，每行添加多个int并添加其他空格分隔符（空格，制表符，换行符）。

好的，所有这些都说明了，只要我将MAX_NUMBERS保持在32k或更低，它就可以工作。如果我提高它，它会很好地显示计数，直到大约32k左右，然后它减慢几百个左右，然后突然挂在32768。由于这个数字，我认为可能必须这样做具有int的大小（在ming编译器中使用代码块），但是sizeof（int）显示它为4个字节，因此不应该引起它。还以为我可能在未使用数组之前就达到了数组索引数量的最大限制。我的研究表明，这不应该是原因。我知道随着要检查重复项的值数量的增加，它的速度将会降低，但是我很困惑为什么它突然停止。

最后，作为实验，我确实尝试将其修改为使用更大的C99数据类型而不是int，但这没有任何作用。

如果有人碰巧看到任何愚蠢的东西，除了使用数组哈哈，请告诉我！这让我有些疯狂。

#include <stdio.h>
#include <stdlib.h>
#include <time.h>


int main()
{
    const int MAX_NUMBERS = 32000; // don't go higher than about 32000
    int* arr;
    // arr is used for duplicate checking, a log of everything put into the file is recorded
    // in arr and checked against to ensure uniqueness.

    const int ALLOW_NEG = 1; // switch to choose whether to allow negative numbers or not.

    int x = 0; // the random number that was generated
    int index = 0; // main loop control
    int index2 = 0; // dupe check loop control
    int hpos = 1; // used to select which type of whitespace to add
    int uniNum = 1; // uniqueness flag
    FILE *f = fopen("nums.txt", "w"); // open the file for writing. creates it if it's not there.

    arr = calloc(MAX_NUMBERS, sizeof(int)); // allocate space for the array

    for (index = 0; index < MAX_NUMBERS; index++) // arr init loop
        arr[index] = 999999999; // init the array to an invalid value. initially was 0, but caused 0 to be omitted by the dupe checker


    if (f == NULL){ // sanity check for the file
        printf("Error: Unable to open file. Program aborting.\n");
        exit(1);
    }

    printf("Generating data file...\n");

    srand(time(NULL)); // seed the random number generator

    fprintf(f, "%d\n", MAX_NUMBERS); // write the first line, the total number of ints in the file

    for (index = 0; index < MAX_NUMBERS; index++) { // main loop
        printf("\r%d", index); // just a display of the indices as the loops running, useless for small counts, semi-useful for very large amounts (100k+)
        do { // check for unique number
            uniNum = 1; // set uniqueness flag
            if (ALLOW_NEG == 1) { // executed if negatives are allowed
                  // This will allow 0, which makes sens if the
                  // range includes negative and positive.
                x = (rand() % MAX_NUMBERS+1) -((MAX_NUMBERS+1)/2); // generate a random number between (-max_nums/2) and (max_nums/2), totaling max_nums. the +1 is a bug fix, ask if curious
            } else { // no negs allowed!
                 // +1 makes the range from 1 to MAX_NUMBERS + 1,
                 // change to zero or remove to range from 0 to MAX_NUMBERS
                x = (rand() % MAX_NUMBERS+1) + 1; // generate random number of only positive ints and 0.
            }

            for (index2 = 0;index2 <= index; index2++){ // check currently generated numbers for dupes
                if (x == arr[index2]) { // dupe found!
                    uniNum = 0; // clear uniqueness flag
                    break; // end the for loop on a dupe, no sense in continuing
                }
            }
        } while(uniNum != 1); // repeat if the number wasn't unique
        arr[index] = x; // log the number

        if (hpos > 4) { // check to see if the horizontal position indicator is greater than 4
            fprintf(f, "%d\n", x); // write to the 5th position horizontally with a newline
            hpos = 1; // reset the horizontal position to the first. this gives me 5 numbers
                      //per line, with differing types of whitespace, just to test the reading
                      //and storing function. see a2.txt
        } else {
            switch (hpos) { // select based on which position we are in
                case 1 :
                    fprintf(f, "%d ", x); // first, space
                    hpos++;
                break;
                case 2 :
                    fprintf(f, "%d\t", x); // second, a tab character
                    hpos++;
                break;
                case 3 :
                    fprintf(f, "%d ", x); // third, another space
                    hpos++;
                break;
                case 4 :
                    fprintf(f, "%d\t", x);// fourth, another tab.. fifth is a newline
                    hpos++;
                break;
            }
        }
    }
    printf("\n%d numbers generated", index); // eh, print it out. why not?

    return 0;
}