Hi ragul
refer this link to count the input from switch using interrupt and display in lcd by erfering these links
http://www.engineersgarage.com/embedded/pic-microcontroller-projects/interface-lcd-circuit
weight can be measured by load cell which will give analog value according to the weight. you get details about load cell and analog to digital interface in below links
http://www.engineersgarage.com/articles/load-cell
http://www.engineersgarage.com/embedded/pic-microcontroller-projects/adc-circuit