thanks for the notes. After change "double infinity" to std::numeric_limits<double>(), here is the output: 1.100000e+00 inf -inf 3.300000e+00
it is clear that the sqlite3 does store "infinity", and select statement can retrieve it as well. The "printf" of C++ prints "infinity" as literal "inf". Michael Chen On Tue, Oct 20, 2009 at 12:20 AM, John Crenshaw <johncrens...@priacta.com>wrote: > Sorry, I think I gave you slightly buggy instructions. I just realized > that max() should be the max true value capable of being stored, which > should be less than the infinity value. std::numeric_limits<double> > provides another function named infinity() for getting positive > infinity. I believe this value will be different than max(). > > Sorry for the mistake. > > John > > -----Original Message----- > From: sqlite-users-boun...@sqlite.org > [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Michael Chen > Sent: Monday, October 19, 2009 11:40 PM > To: General Discussion of SQLite Database > Subject: Re: [sqlite] Infinity > > Thanks John. After incorporate a few changes, the code can compile and > run. > The result seems reasonable, the input infinity > std::numeric_limits<double>::max() is sent to and retrieved from a > sqlite3 > database correctly. > > --terminal output > > sqlite3 tempdb > > sqlite> select * from tl; > 1.1 > 1.79769313486232e+308 > -1.79769313486232e+308 > 3.3 > > > --source code -- > > #include <limits> > #include <string> > #include <iostream> > #include <cassert> > #include <sqlite3.h> > using namespace std; > > int main(){ > double infinity = std::numeric_limits<double>::max(); > double ninfinity = - std::numeric_limits<double>::max(); > sqlite3 *db; > char *zErrMsg = 0; > int rc; > rc = sqlite3_open("tempdb", &db); > if( rc ){ > fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db)); > sqlite3_close(db); > exit(1); > } > > sqlite3_stmt* create_tl; > rc = sqlite3_prepare_v2(db, "create table tl (number real)", -1, > &create_tl,NULL); > > if ( rc != SQLITE_OK) exit(rc); > rc = sqlite3_step(create_tl); > if ( rc != SQLITE_DONE) exit(rc); > > sqlite3_stmt* insert_tl; > rc = sqlite3_prepare_v2(db,"insert into tl values(:number)",-1, > &insert_tl,NULL); > if ( rc != SQLITE_OK) exit(rc); > > sqlite3_bind_double(insert_tl, 1, 1.1); > rc = sqlite3_step(insert_tl); > if (rc != SQLITE_DONE) > exit(rc); > > sqlite3_reset(insert_tl); > sqlite3_bind_double(insert_tl, 1, infinity); > rc = sqlite3_step(insert_tl); > if (rc != SQLITE_DONE) > exit(rc); > > sqlite3_reset(insert_tl); > sqlite3_bind_double(insert_tl, 1, ninfinity); > rc = sqlite3_step(insert_tl); > if (rc != SQLITE_DONE) > exit(rc); > > sqlite3_reset(insert_tl); > sqlite3_bind_double(insert_tl, 1, 3.3); > rc = sqlite3_step(insert_tl); > if (rc != SQLITE_DONE) > exit(rc); > > > sqlite3_stmt* select_tl; > rc = sqlite3_prepare_v2(db, "select * from tl",-1,&select_tl,NULL); > if (rc != SQLITE_OK) > exit(rc); > > while ( sqlite3_step(select_tl) == SQLITE_ROW){ > printf("%e",sqlite3_column_double(select_tl,0)); > printf("\n"); > } > > if (rc != SQLITE_DONE) > exit(rc); > sqlite3_finalize(select_tl); > > sqlite3_close(db); > printf("exit normally\n"); > } > > > > > -- > Best regards, > Michael Chen > Google Voice Phone.: 847-448-0647 > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- Best regards, Michael Chen Google Voice Phone.: 847-448-0647 _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
