diff --git a/examples/C/pres_temp_4D_rd.c b/examples/C/pres_temp_4D_rd.c
index 6cdfce738..d6d44814c 100644
--- a/examples/C/pres_temp_4D_rd.c
+++ b/examples/C/pres_temp_4D_rd.c
@@ -79,7 +79,7 @@ main()
    float lats[NLAT], lons[NLON];
 
    /* Loop indexes. */
-   int lvl, lat, lon, rec, i = 0;
+   int lvl, lat, lon, i = 0;
    
    /* Error handling. */
    int retval;
@@ -128,7 +128,7 @@ main()
    start[3] = 0;
 
    /* Read and check one record at a time. */
-   for (rec = 0; rec < NREC; rec++)
+   for (size_t rec = 0; rec < NREC; rec++)
    {
       start[0] = rec;
       if ((retval = nc_get_vara_float(ncid, pres_varid, start, 
diff --git a/examples/C/pres_temp_4D_wr.c b/examples/C/pres_temp_4D_wr.c
index 3820b1627..5b5452f13 100644
--- a/examples/C/pres_temp_4D_wr.c
+++ b/examples/C/pres_temp_4D_wr.c
@@ -78,7 +78,7 @@ main()
    float lats[NLAT], lons[NLON];
 
    /* Loop indexes. */
-   int lvl, lat, lon, rec, i = 0;
+   int lvl, lat, lon, i = 0;
 
    /* Error handling. */
    int retval;
@@ -188,7 +188,7 @@ main()
       surface temperature data. The arrays only hold one timestep worth
       of data. We will just rewrite the same data for each timestep. In
       a real application, the data would change between timesteps. */
-   for (rec = 0; rec < NREC; rec++)
+   for (size_t rec = 0; rec < NREC; rec++)
    {
       start[0] = rec;
       if ((retval = nc_put_vara_float(ncid, pres_varid, start, count,