can you help me guys pls!!!

[tayf]

Write a program to determine the value Y given the argument X of a function presented by linked segments, i.e. by a sequence of N points (X(1),Y(1)), (X(2),Y(2)), . . . , (X(N),Y(N)).

[methodos]

http://cboard.cprogramming.com/cplusplus-programming/136974-hi-guys-my-homework-f-you-make-ill-very-happy-thanx.html
Homework???? It's not allowed.
Anyway, I don't know what you mean by

a function presented by linked segments.

Look in your textbook. It'll be there, I guess.