first semester files

1st-Semester-Fall-2021/CSNP/FISR/fisr.cpp

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+#include <iostream>
+#include <string>
+
+using namespace std;
+
+float Q_rsqrt( float number )
+{
+    long i;
+    float x2, y;
+    const float threehalfs = 1.5F;
+
+    x2 = number * 0.5F;
+    y = number;
+    i = * ( long * ) &y;                        // evil floating point bit level hacking
+    i = 0x5f3759df - ( i >> 1 );                // what the fuck
+    y = * ( float * ) &i;                       
+    y = y * ( threehalfs - ( x2 * y * y ) );    // 1st iteration
+    y = y * ( threehalfs - ( x2 * y * y ) );    // 2nd iteration, can be removed
+
+    return y;
+}
+
+int main()
+{
+    int number;
+    cin >> number;
+    cout << Q_rsqrt( number );
+    return 0;
+}