Financial Instrument Pricing Using C -
We use the erfc (complementary error function) to calculate the cumulative distribution function, which is the probability that the option will end up "in the money."
This code calculates the theoretical price of an option based on the underlying price, strike price, time to maturity, risk-free rate, and volatility. Financial Instrument Pricing Using C
In a production environment, you would extend this to calculate Delta , Gamma , and Theta by taking the partial derivatives of the price function. We use the erfc (complementary error function) to
#include #include // Cumulative Normal Distribution Function (approximation) double normal_cdf(double x) { return 0.5 * erfc(-x * M_SQRT1_2); } // Black-Scholes Formula for a European Call Option double calculate_call_price(double S, double K, double T, double r, double sigma) { double d1 = (log(S / K) + (r + 0.5 * sigma * sigma) * T) / (sigma * sqrt(T)); double d2 = d1 - (sigma * sqrt(T)); double price = S * normal_cdf(d1) - K * exp(-r * T) * normal_cdf(d2); return price; } int main() { // Parameters double stock_price = 100.0; // Spot price (S) double strike_price = 105.0; // Strike price (K) double time_to_expiry = 1.0; // Years (T) double risk_free_rate = 0.05; // 5% (r) double volatility = 0.20; // 20% (sigma) double price = calculate_call_price(stock_price, strike_price, time_to_expiry, risk_free_rate, volatility); printf("--- Option Pricing Engine ---\n"); printf("Underlying Price: %.2f\n", stock_price); printf("Strike Price: %.2f\n", strike_price); printf("Call Option Price: %.4f\n", price); return 0; } Use code with caution. Copied to clipboard Components of the Engine Copied to clipboard Components of the Engine The
The library provides the necessary transcendental functions ( the square root of empty end-root
C is ideal for this because pricing engines often need to run thousands of iterations (Monte Carlo simulations) in milliseconds. The Implementation: Black-Scholes Call Option
Since this uses stack-allocated doubles, it is extremely fast and can be called inside a loop for "Greeks" sensitivity analysis or volatility surfaces.