diff --git a/src/USER-MISC/dihedral_nharmonic.cpp b/src/USER-MISC/dihedral_nharmonic.cpp
index 8def32bb35..87f7b0775b 100644
--- a/src/USER-MISC/dihedral_nharmonic.cpp
+++ b/src/USER-MISC/dihedral_nharmonic.cpp
@@ -343,10 +343,10 @@ void DihedralNHarmonic::read_restart(FILE *fp)
 void DihedralNHarmonic::write_data(FILE *fp)
 {
   for (int i = 1; i <= atom->ndihedraltypes; i++) {
-    fprintf(fp, "%d %d ", i, nterms[i]);
-    for (int j = 0; j < nterms[i]; j++ ) {
-      fprintf(fp, (j < nterms[i] - 1) ? "%f " : "%f", a[i][j]);
-    }
+    fprintf(fp, "%d %d", i, nterms[i]);
+    for (int j = 0; j < nterms[i]; j++ )
+      fprintf(fp, " %g", a[i][j]);
+
     fprintf(fp, "\n");
   }