how to auto generate an excel format file contains formula using C

hi,
now i have a problem, i want to auto create an excel file using C++ language.

i have an data.log file, and the format list below:
1,3,0,...,1,2,
.....
2,0,0,...,3,1,

i want to wirte an C++ program that can read the data.log, anlyse it and
then write the datas to EXCEL format files with formula, like:
get line 1 in data.log, and the first value "1" write to A1, and "3" to
B1,"0" to C1,etc
get line 2 in data.log, and the first value to A2,then the sencond to
B2,...etc.

and addition, i want to set the grid width and height to 15.75, also i want
to set some formule to those cell which contains datas, the formule is: if
the value greater than 0, then the background color of the cell is red else
is green.


so if i want to using C++ complete this task, which tools or libs i need?
and how to do? Is there anything tutorial ?

thanks in advance