initial commit

junet/Auth/auth.c

@@ -0,0 +1,71 @@
+#include "auth.h"
+
+
+ld
+toRadians(ld degree){
+    ld one_deg = (M_PI)/180;
+    return (one_deg * degree);
+}
+
+ld
+sq_root(ld value){
+    ld err = 1e-10;
+
+    ld ans = 0;
+    ld low = 0 , high = 0;
+
+	if(value < 1){
+		low = value , high = 1;
+	}
+	else{
+		low = 1 , high = value;
+	}
+
+    for(int i = 1 ; i <= 67 ; i++ ){
+
+        ld mid = low + (high - low)/2.0;
+
+        if( mid*mid <= value ){
+            ans = mid;
+            low = mid + err;
+        }
+        else{
+            high = mid - err;
+        }
+    }
+
+    return ans;
+}
+
+ld
+orthodromic_distance(ld stu_lat,ld stu_long,ld teach_lat,ld teach_long){
+    stu_lat = toRadians(stu_lat);
+    stu_long = toRadians(stu_long);
+    teach_lat = toRadians(teach_lat);
+    teach_long = toRadians(teach_long);
+
+    ld diff_lat = teach_lat - stu_lat;
+    ld diff_long = teach_long - stu_long;
+
+    ld ans = pwr2(sin(diff_lat/2)) +
+                cos(stu_lat) * cos(teach_lat) *
+                pwr2(sin(diff_long/2));
+
+    ans = 2 * asin(sq_root(ans));
+
+
+    // Radius of Earth in
+    // Kilometers, R = 6371
+    // Use R = 3956 for miles
+    ld R = 6371;
+
+	//ans in meter...
+    ans = ans * R * (ld)1000;
+    return ans;
+}
+
+bool
+check_range(ld dist){
+    //better implementation for future....
+    return dist <= (ld)100;
+}