Visual studio error: implicit declaration of function

Question

why is this error coming implicit declaration of function 'scanf_s'. scanf is not working in visual studio even after writing scanf_s instead of scanf?.

#include<stdio.h>
int main()
{
    printf("hello\n");
    int a;
    scanf_s("%d", &a);
    printf("\n%d",a);
    return 0;
}