From 2f85db6f4380f323e769d6111b6976d9346654ef Mon Sep 17 00:00:00 2001
From: Ta180m
Date: Tue, 28 Apr 2020 21:39:05 -0500
Subject: Add files via upload

---
 SARS in Hong Kong.xlsx | Bin 0 -> 8246 bytes
 sir_model.cpp          |  48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 SARS in Hong Kong.xlsx
 create mode 100644 sir_model.cpp

diff --git a/SARS in Hong Kong.xlsx b/SARS in Hong Kong.xlsx
new file mode 100644
index 0000000..f53cee9
Binary files /dev/null and b/SARS in Hong Kong.xlsx differ
diff --git a/sir_model.cpp b/sir_model.cpp
new file mode 100644
index 0000000..f054c36
--- /dev/null
+++ b/sir_model.cpp
@@ -0,0 +1,48 @@
+#include <iostream>
+#include <iomanip>
+using namespace std;
+
+// Iterations for Euler's method
+const int DAYS = 200, ITER = 10000;
+
+// Population size
+const int POP = 2000;
+
+// Model parameters
+// Beta = infection rate
+// Gamma = removal rate
+const double beta = 0.42, gamma = 0.25;
+
+// Compartments
+double S[DAYS + 1], I[DAYS + 1], R[DAYS + 1];
+
+int main() {
+    // Initial conditions
+    S[0] = 1 - 1.0 / POP, I[0] = 1.0 / POP, R[0] = 0;
+    
+    // Run simulation
+    for (int i = 0; i < DAYS; ++i) {
+        double S_[ITER + 1], I_[ITER + 1], R_[ITER + 1];
+        
+        S_[0] = S[i], I_[0] = I[i], R_[0] = R[i];
+        
+        // Euler's method
+        for (int j = 0; j < ITER; ++j) {
+            S_[j+1] = S_[j] + (-beta * S_[j] * I_[j]) / ITER;
+            I_[j+1] = I_[j] + (beta * S_[j] * I_[j] - gamma * I_[j]) / ITER;
+            R_[j+1] = R_[j] + (gamma * I_[j]) / ITER;
+        }
+        
+        S[i + 1] = S_[ITER], I[i + 1] = I_[ITER], R[i + 1] = R_[ITER];
+    }
+    
+    // Print results
+    cout << "| DAY | SUSCEPTIBLE |  INFECTIOUS |   RECOVERED |\n";
+    cout << "-------------------------------------------------\n";
+    for (int i = 0; i < DAYS; ++i) {
+        cout << "| " << setw(3) << i << " | "; // Day
+        cout << setw(11) << (int)(POP * S[i] + .5) << " | "; // Suspectible
+        cout << setw(11) << (int)(POP * I[i] + .5) << " | "; // Infectious
+        cout << setw(11) << (int)(POP * R[i] + .5) << " |\n"; // Recovered
+    }
+}
\ No newline at end of file
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