diff --git a/lib/gpu/lal_pppm.cpp b/lib/gpu/lal_pppm.cpp
index 87ab6fe775..bbdaf76036 100644
--- a/lib/gpu/lal_pppm.cpp
+++ b/lib/gpu/lal_pppm.cpp
@@ -54,7 +54,7 @@ int PPPMT::bytes_per_atom() const {
 }
 
 template <class numtyp, class acctyp, class grdtyp, class grdtyp4>
-grdtyp * PPPMT::init(const int nlocal, const int nall, FILE *_screen,
+grdtyp *PPPMT::init(const int nlocal, const int nall, FILE *_screen,
                               const int order, const int nxlo_out,
                               const int nylo_out, const int nzlo_out,
                               const int nxhi_out, const int nyhi_out,
@@ -69,14 +69,14 @@ grdtyp * PPPMT::init(const int nlocal, const int nall, FILE *_screen,
 
   flag=device->init(*ans,nlocal,nall);
   if (flag!=0)
-    return 0;
+    return nullptr;
   if (sizeof(grdtyp)==sizeof(double) && device->double_precision()==false) {
     flag=-15;
-    return 0;
+    return nullptr;
   }
   if (device->ptx_arch()>0.0 && device->ptx_arch()<1.1) {
     flag=-4;
-    return 0;
+    return nullptr;
   }
 
   ucl_device=device->gpu;
diff --git a/src/compute_bond_local.cpp b/src/compute_bond_local.cpp
index 275924d0e5..8818f15fb7 100644
--- a/src/compute_bond_local.cpp
+++ b/src/compute_bond_local.cpp
@@ -221,7 +221,7 @@ void ComputeBondLocal::compute_local()
 
 int ComputeBondLocal::compute_bonds(int flag)
 {
-  int i,m,n,nb,atom1,atom2,imol,iatom,btype,ivar;
+  int i,m,nb,atom1,atom2,imol,iatom,btype,ivar;
   tagint tagprev;
   double dx,dy,dz,rsq;
   double mass1,mass2,masstotal,invmasstotal;
@@ -261,7 +261,7 @@ int ComputeBondLocal::compute_bonds(int flag)
 
   // loop over all atoms and their bonds
 
-  m = n = 0;
+  m = 0;
   for (atom1 = 0; atom1 < nlocal; atom1++) {
     if (!(mask[atom1] & groupbit)) continue;
 
@@ -304,6 +304,8 @@ int ComputeBondLocal::compute_bonds(int flag)
       } else {
 
         if (singleflag) engpot = bond->single(btype,rsq,atom1,atom2,fbond);
+        else fbond = engpot = 0.0;
+        engvib = engrot = engtrans = omegasq = vvib = 0.0;
 
         if (velflag) {
           if (rmass) {
@@ -383,7 +385,7 @@ int ComputeBondLocal::compute_bonds(int flag)
           if (dstr) input->variable->internal_set(dvar,sqrt(rsq));
         }
 
-        for (n = 0; n < nvalues; n++) {
+        for (int n = 0; n < nvalues; n++) {
           switch (bstyle[n]) {
           case DIST:
             ptr[n] = sqrt(rsq);
diff --git a/src/utils.cpp b/src/utils.cpp
index 7262cf8afd..866b3773d1 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -583,8 +583,8 @@ int utils::expand_args(const char *file, int line, int narg, char **arg, int mod
 
       // split off the compute/fix/property ID, the wildcard and trailing text
 
-      size_t first = word.find("[");
-      size_t second = word.find("]", first + 1);
+      size_t first = word.find('[');
+      size_t second = word.find(']', first + 1);
       if (word[1] == '2')
         id = word.substr(3, first - 3);
       else