php random into from -1 to 1 code example

Example 1: how to generate random between 0 and 9 in c

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

int main()

{
    int randomnumber;
    srand(time(NULL));
    randomnumber = rand() % 10;
    printf("%d\n", randomnumber);
    return 0;
}

Example 2: c# random number between 0 and 1

Random rand = new Random();
return rand.NextDouble; //returns a random number bw 0.0 and 1.0!