open the file\"data.txt\"
Caluculate the real value
close the file:\"data.txt\"open the file:\"result.txt\"
Start
Line ++
Read and record the data:store the first data into x[i];store the second data into y[i]
Ask users to make choice
Choose 2
Any data reserved ?
close the file:\"result.txt\"
The first type:straight line
Choose 1
The second type: polynomial equation
End