Must program this in C. Any help?

this is the starter code

4 double two_d_random(int n) //Fill in code below //You are fee to write some other functions this function //Allocate memory for all the integer (x, y) coordinates inside the boundary //A1locate just one memory block //Figure out how to map between (x, y) and the index of the array //we can treat this allocated memory block as an integer array //write a function for this mapping if needed //when deciding which way to go for the next step, generate a random number as follows //r- rand() % 4; //Treat r=e, 1, 2, 3 as moving up, right, down and left respectively. //The random walk should stop once the x coordinate or y coordinate reaches $-ns or $n$ //The function should return the fraction of the visited $(x, y)$ coordinates inside (not including) the square. 21 //Do not forget to free the allocated memory block before the function ends. 24 25 //Do not change the code below 26 int main) int trials = 1000; srand (12345); for(int n-1i n