插入排序的函数为什么不对

Question

想问一下，编写一个插入排序函数，然后在主函数测试，这个程序哪里错了
源代码如下

#include <iostream>
using namespace std;
void order(int a[12], int n) {
    
    for (int i = 2; i <= n; i++) {
        int j, x = a[i];
        for (j = i; j > 1 && a[j - 1] > x; j--) {
            a[j] = a[j - 1];
        }
        a[j] = x;
    }
    for (int i = 0; i < n; i++) {
        cout << a[i] << " ";
    }
 }
 int main() {
     int a[5] = { 2,1,4,5,7 };
     int n = sizeof(a) / sizeof(a[0]);
     
     order(a, n);
     for (int i = 0; i < n; i++)
         cout << a[i] << " ";
    return    0;
    
    
}

程序没有报错，运行的时候系统崩了

Answer 1

改动处见注释，供参考：

#include <iostream>
using namespace std;
void order(int a[12], int n) {

    for (int i = 1; i < n; i++) { //(int i = 2; i <= n; i++) 修改
        int j, x = a[i];
        for (j = i; j > 0 && a[j - 1] > x; j--) { //for (j = i; j > 1 && a[j - 1] > x; j--) 修改
            a[j] = a[j - 1];
        }
        a[j] = x;
    }
    for (int i = 0; i < n; i++) {
        cout << a[i] << " ";
    }
    cout<<endl;  //修改
 }
 int main() {
     int a[5] = { 2,1,4,5,7 };
     int n = sizeof(a) / sizeof(a[0]);

     order(a, n);
     for (int i = 0; i < n; i++)
         cout << a[i] << " ";
     return 0;
}