使用 sprintf 时设置变量长度的注意

代码：

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
int main()
{
    char h[17];
    for (int i = 0; i < 17; i++)
        cout << (int)h[i] << ", ";
    cout << endl << endl;
    unsigned long long a = 0x1234567890abcd;
    sprintf(h, "%016I64x", a);
    for (int i = 0; i < 17; i++)
        cout << (int)h[i] << ", ";
}

结果:

-52, -52, -52, -52, -52, -52, -52, -52, -52, -52, -52, -52, -52, -52, -52, -52, -52,

48, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 48, 97, 98, 99, 100, 0

证明：

sprintf 中 "%016I64x" 将最后的 '\0' ,复制给了 h，所以 h 需要 17 字节