diff --git a/Julian.cpp b/Julian.cpp
index 652a73f..41f4d76 100644
--- a/Julian.cpp
+++ b/Julian.cpp
@@ -173,7 +173,7 @@ time_t Julian::ToTime() const {
     // the fractional portion of day.
     int nDOM = (int) dblDay;
 
-    dblDay -= nDOM;
+    dblDay = dblDay - nDOM;
 
     const int SEC_PER_MIN = 60;
     const int SEC_PER_HR = 60 * SEC_PER_MIN;
@@ -202,7 +202,7 @@ time_t Julian::ToTime() const {
         // Valid time_t value returned from mktime().
         // mktime() expects a local time which means that tEpoch now needs
         // to be adjusted by the difference between this time zone and GMT.
-        //		tEpoch -= _timezone;
+        //		tEpoch = tEpoch - _timezone;
     }
 
     return tEpoch;
diff --git a/SGDP4.cpp b/SGDP4.cpp
index 6cd1bd1..3d646b3 100644
--- a/SGDP4.cpp
+++ b/SGDP4.cpp
@@ -284,8 +284,8 @@ void SGDP4::FindPositionSDP4(Eci& eci, double tsince) {
     }
 
     a = pow(constants_.XKE / xn, constants_.TWOTHRD) * pow(tempa, 2.0);
-    e -= tempe;
-    
+    e = e - tempe;
+
     /*
      * fix tolerance for error recognition
      */
@@ -318,7 +318,7 @@ void SGDP4::FindPositionSDP4(Eci& eci, double tsince) {
     if (xincl < 0.0) {
         xincl = -xincl;
         xnode += Globals::PI();
-        omgadf -= Globals::PI();
+        omgadf = omgadf - Globals::PI();
     }
 
     xl = xmam + omgadf + xnode;
@@ -394,12 +394,12 @@ void SGDP4::FindPositionSGP4(Eci& eci, double tsince) const {
         const double temp = delomg + delm;
 
         xmp += temp;
-        omega -= temp;
+        omega = omega - temp;
 
         const double tcube = tsq * tsince;
         const double tfour = tsince * tcube;
 
-        tempa -= i_d2_ * tsq - i_d3_ * tcube - i_d4_ * tfour;
+        tempa = tempa - i_d2_ * tsq - i_d3_ * tcube - i_d4_ * tfour;
         tempe += BStar() * i_c5_ * (sin(xmp) - i_sinmo_);
         templ += i_t3cof_ * tcube + tfour * (i_t4cof_ + tsince * i_t5cof_);
     }
@@ -1049,7 +1049,7 @@ void SGDP4::DeepSpacePeriodics(const double& t, double& em,
                 if (xnodes < oldxnodes)
                     xnodes += Globals::TWOPI();
                 else
-                    xnodes -= Globals::TWOPI();
+                    xnodes = xnodes - Globals::TWOPI();
             }
 
             xll += pl;
@@ -1188,7 +1188,7 @@ void SGDP4::DeepSpaceCalcDotTerms(double& xndot, double& xnddt, double& xldot) c
     }
 
     xldot = d_xni_ + d_xfact_;
-    xnddt *= xldot;
+    xnddt = xnddt * xldot;
 }
 
 /*
diff --git a/main.cpp b/main.cpp
index 7d1a4d0..ae6e2e5 100644
--- a/main.cpp
+++ b/main.cpp
@@ -424,7 +424,7 @@ void RunTest() {
             "1 29141U 85108AA  06170.26783845  .99999999  00000-0  13519-0 0   718",
             "2 29141  82.4288 273.4882 0015848 277.2124  83.9133 15.93343074  6828"), 0.0, 420.0, 20.0);
 
-return;
+    return;
     /*
     #   SL-12 DEB           # Near Earth, perigee = 212.24 < 220
     #                       # simplified drag eq