c - 使用指针返回数组的总和 - 无输出

Question

我正在编写一个函数来返回数组的总和，但我的测试用例显示该特定函数没有输出。有人可以帮忙吗？

double sumArray(int n, double * array) {
    // Add your code here
    int i; 
    double sum = 0.000000;
    double *ptr;
    ptr = array;
    if (n == 0) {
        return 0.000000;
    } else {
        for (i = 0; i < n; i++) {
            sum = sum + *ptr;
            ptr++;
        }
        return sum;
    }
}

Answer 1

这更干净，更易读(我认为)，也更安全。

double sumArray(const double * const arr, size_t n) {
    // promise the compiler that you won't change anything in the array or the pointer itself
    // the size of an array should always be >= 0, so use a size_t
    double sum = 0.0;
    const double *ptr = arr; // create a const pointer and point it at the array
    size_t i; // counter variable
    for (i = 0; i < n; ++i) // iterate up to n
        sum += *ptr++; // dereference ptr and increment it
    return sum;
}


int main(int argc, char **argv) {
    double arr[] = { 1.0, 1.5, 2.1 };
    printf("%f\n", sumArray(arr, sizeof(arr)/sizeof(double)));
    return 0;
}