fixed warnings by replacing strcat with string_format

src/Eofcoeff.cc

@@ -148,16 +148,12 @@ public:
     streamIDs = std::vector<CdoStreamID>(neof);
     for (eofID = 0; eofID < neof; eofID++)
       {
-        oname[nchars] = '\0';
+        std::string file_name = MpMO::string_format("%s%5.5i%s", oname, eofID, filesuffix[0] ? filesuffix : "");
 
-        sprintf(eof_name, "%5.5i", eofID);
-        strcat(oname, eof_name);
-        if (filesuffix[0]) strcat(oname, filesuffix);
-
-        streamIDs[eofID] = cdo_open_write(oname);
+        streamIDs[eofID] = cdo_open_write(file_name);
 
         if (Options::cdoVerbose)
-          cdo_print("opened %s ('w')  as stream%i for %i. eof", oname, streamIDs[eofID]->get_id(), eofID + 1);
+          cdo_print("opened %s ('w')  as stream%i for %i. eof", file_name, streamIDs[eofID]->get_id(), eofID + 1);
 
         cdo_def_vlist(streamIDs[eofID], vlistID3);
       }

src/Eofcoeff3d.cc

@@ -158,11 +158,13 @@ public:
       {
         oname[nchars] = '\0';
 
-        sprintf(eof_name, "%5.5i", eofID);
-        strcat(oname, eof_name);
-        if (filesuffix[0]) strcat(oname, filesuffix);
 
-        streamIDs[eofID] = cdo_open_write(oname);
+        //sprintf(eof_name, "%5.5i", eofID);
+        //strcat(oname, eof_name);
+        //if (filesuffix[0]) strcat(oname, filesuffix);
+
+        std::string file_name = MpMO::string_format("%s%5.5i%s", oname, eofID, filesuffix[0] ? filesuffix : "");
+        streamIDs[eofID] = cdo_open_write(file_name);
 
         if (Options::cdoVerbose)
           cdo_print("opened %s ('w')  as stream%i for %i. eof", oname, streamIDs[eofID]->get_id(), eofID + 1);