How can i pass a veriable in mysql_qeury through c language

I wand to pass a varible in mysql_query
through c coding
this should work

String query,acctnbr,amount;

accntnbr = [(whatever the variable is)];
amount = [(whatever the variable is)];

query = "insert into tablename (acctnbr,amount) values (%s,%s)",acctnbr,amount);
mysql_query(&mysql,query);
How can i pass the variable in values
thanks