Adding variables to char *

Question

I would like to change the values in my char * to the int and double that are declared so I can change them without touching char *sql. (on ubuntu using C)

How can i do this?

code:

int sensor_id = 10;

double temp = 22.22;

char *sql = "INSERT INTO test_table(sensor_id, sensor_value) VALUES(10, 22.22)";

What platform? For POSIX linux.die.net/man/3/wordexp

Šimon Tóth
– Šimon Tóth

2015-04-21 13:55:28 +00:00
Commented Apr 21, 2015 at 13:55 — Šimon Tóth
– Šimon Tóth, Commented Apr 21, 2015 at 13:55

Jabberwocky · Accepted Answer · 2015-04-21 13:55:05Z

2

Try this (dirty, no error checking, buffer overflow may occur):

const char *sqlformat = 
            "INSERT INTO test_table(sensor_id, sensor_value) VALUES(%d, %f)";

char sql[200];
sprintf(sql, sensor_id, temp);

Now you have what you want in the sql buffer.

This is very basic C stuff, I suggest you to learn C.

answered Apr 21, 2015 at 13:55

Jabberwocky

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