How do I find the insecurity in this code fragment?

Your code fragment isn't complete: you need to use the code widget to engage the syntax highlighter (or paste it with the "Code block" option set) I suspect.

But while we are more than willing to help those that are stuck, that doesn't mean that we are here to do it all for you! We can't do all the work, you are either getting paid for this, or it's part of your grades and it wouldn't be at all fair for us to do it all for you.

So we need you to do the work, and we will help you when you get stuck. That doesn't mean we will give you a step by step solution you can hand in!
Start by explaining where you are at the moment, and what the next step in the process is. Then tell us what you have tried to get that next step working, and what happened when you did.

So run it, look at it, and see what you can see that the user might do that would be outside of what he should be allowed!

I have added code to make it run and entered characters. I learned the input can be more than 8 characters but it will only display 8 on the screen that is the intended function. I am not trying to use the strcpy_s function and I am going through all blogs and posts. I spend hours reading and learning the concepts. I am not a programmer but trying to learn the basics for to complete my class. Below is my code where I am getting this error "strcpy_s’ was not declared in this scope" I will continue to research the issue.

#include <iostream>
#include <string.h>
using namespace std;

void sampleFunc(char inStr[])
{
char buf[10];
buf[9] ='\0';
strcpy_s(buf,inStr);
cout <<"\n" <<buf<<"\n";
return;
}
int="" main(){
char="" instr[10];
cout<<"enter="" string:="" ";
cin="">>inStr;
sampleFunc(inStr);

}