difftime problem

[weipin0104]

question:
Participants are required to answer as many questions as possible in 60 seconds.

how should i use the difftime(time_t, time_t) function to stop user from key in anythings as time reach 61th seconds?

thanks.

[Athar]

See http://www.cplusplus.com/reference/clibrary/ctime/difftime/