adding 0069-sqrtx.c

Author: PritomKarmokar

Diff for: c/0069-sqrtx.c

@@ -0,0 +1,18 @@
+int mySqrt(int x){
+    int l = 0;
+    int r = x;
+
+    while(l <= r){
+        long int m = (l + r) / 2;
+        if(m * m == x){
+            return m;
+        }
+        else if(m * m > x){
+            r = m - 1;
+        }
+        else{
+            l = m + 1;
+        }
+    }
+    return r;
+}