i have done a program in C but ther is an error maseeg
it is:

--------------------Configuration: ..... - Win32 Debug--------------------
Compiling...
......c
d:\program files\microsoft visual studio\vc98\include\conio.h(177) : warning C4229: anachronism used : modifiers on data are ignored
D:\......c(33) : warning C4244: '=' : conversion from 'double ' to 'float ', possible loss of data
D:\......c(47) : warning C4013: 'free' undefined; assuming extern returning int
D:\......c(87) : warning C4013: 'sertch' undefined; assuming extern returning int
D:\......c(112) : warning C4013: 'malloc' undefined; assuming extern returning int
D:\......c(112) : warning C4047: '=' : 'struct node *' differs in levels of indirection from 'int '
D:\......c(153) : warning C4013: 'system' undefined; assuming extern returning int
Linking...
......obj : error LNK2001: unresolved external symbol _sertch
Debug/......exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

......exe - 2 error(s), 7 warning(s)

forgut abut the warning i dont know what is
the error....????

please help me :