这是我写的程序：

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

void meanVariance(double* x, int n, double* mean, double* variance);
double* scanVector(int length);

void meanVariance(double* x, int n, double* mean, double* variance){
    double sum = 0;

    for (int i = 0; i < n; i++){
        sum += x[i];
    }

    *mean = sum / ((double)n);

    sum = 0;

    for (int i = 0; i < n; i++)
    {
        double sq = x[i] - *mean;
        sum += sq * sq;
    }

    if (n != 1)
    {
        *variance = sum / ((double)n );
    }
    else
    {
        *variance = 1;
    }

}

int main() {
    double *x = malloc(sizeof(double)), mean = 0, variance = 0;
    int n = 0;
    do {
        n++;
        x = realloc(x, sizeof(double) * (n));
        printf("Type in the %d- Number 

: ", n);
        scanf("%lf", (x+(n-1)));
        meanVariance(x, n, &mean, &variance);
        printf("Mittelwert: %f\n", mean);
        printf("Varianz: %f\n", variance);
    } while(*(x+(n-1)) != 0);
    free(x);
}

我不明白为什么scanf函数中没有&。程序可以运行，但我不明白为什么缺少&。我猜它与指针x有关，但我一点也不确定。