diff --git a/chapter08/ex04_approx_int.cpp b/chapter08/ex04_approx_int.cpp
new file mode 100644
index 0000000..b121e1a
--- /dev/null
+++ b/chapter08/ex04_approx_int.cpp
@@ -0,0 +1,32 @@
+#include <iostream>
+#include <vector>
+#include <stdexcept>
+using namespace std;
+
+// pass by const reference
+void print(string label, const vector<int>& v){
+    cout << label << endl;
+    for(int x: v){
+        cout << x << " ";
+    }
+    cout << endl;
+
+}
+
+// keep generating integers until we have an overflow
+int fibonacci(int x, int y, vector<int>& v){
+    v.push_back(x);
+    v.push_back(y);
+    while(y > x){
+        int z = x + y;
+        v.push_back(z);
+        x = y;
+        y = z;
+    }
+    return x;
+}
+
+int main(){
+    vector<int> v;
+    cout << fibonacci(1, 2, v);
+}