求左闭右开区间的元素和

#include<stdio.h>

//方法一
int sum1(int* begin, int* end)
{
    int n =end - begin;
    int sum = 0;
    for (int i = 0; i < n; i++)
    {
        sum += begin[i];
    }
    return  sum;
}

//方法二
int sum2(int* begin, int* end)
{
    int* p = begin;
    int sum = 0;
    for (; p < end; p++)
        sum += *p;
    return sum;
}
int main(void)
{
    //求左闭右开区间内的元素和
    int arr[5] = { 1,2,3,4,5 };
    int a = sum1(arr, &arr[2]);
    printf("%d", a);

    int b = sum2(arr, &arr[2]);
    printf("    %d", b);
    return 0;
}