为什么我的程序返回5？

Question

I study templates and I must search max element < 0. But function return 5.

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

template <class Tdata, class Tnumber>
Tnumber min_max (Tdata arr[], Tnumber n)
{
    int i, p = 0,max_el=0;
    int a=0;
    Tdata arr_help[n];
    for (i=0; i<n; i++){
       if (0 > arr[i]){
            arr_help[a]=arr[i];
            printf("\n a = %i \n",a);
            a++;
        };
        printf("\narr_help = %i\n",arr_help[i]);
    }
    for (i=0;i<a;i++){
        printf("\n p = %i \n",p);
        if(arr_help[p]<arr_help[i+1]) p=i+1;
    }
    printf("\n p_bf_answr = %i \n",p);
    return p;
}

If you start this code, p at the end is 5

int main(){
    srand(time(0));
    int n=5, arr_int[n],i;
    //float arr_float[n];
    printf("\n");
    for (i=0;i<n;i++){
        arr_int[i]=(int)(-(rand()%11 +1));
    }
    printf("\nint_min = %i\n",(min_max(arr_int,n)));
   /* for (i=0;i<n;i++){
        arr_float[i]=(float)(-(rand()%10));
    }
    printf("\nfloat_min = %i\n",((int)min_max(arr_float,n)));*/
    return 0;
}

And I don't know, what I must write here. What details need this site?

Answer 1

In the last time the loop

for (i=0;i<a;i++){
    printf("\n p = %i \n",p);
    if(arr_help[p]<arr_help[i+1]) p=i+1;
}

if executed you compare

if(arr_help[p]<arr_help[a]) p=a;

but arr_help[a] was never set and is possibly beyond the array bounds of arr_help . It may contain anything, thus setting p=a.