how cretae time dependent variable in simulink matlab?

hi,i had a question,i want to in simulink matlab,defined a time dependent variable. for example

v=t+1

how i can create it?please answer me.thanks

Answer 1

[Azzi Abdelmalek]

Use a clock block to generate a time.

[stack programer]

when i for constant v that now it should be variable clock it returns

The current directory 'd:\matlab\matlab production server\r2015a\bin' is reserved for MATLAB files.

   Please change your current directory to a writeable directory outside of the MATLAB installation area.
  Component: Stateflow | Category: General error

i want to display block is change with time,with this method it is only show a value if even this error is fixed. any way thanks for reply

[stack programer]

i fixed errors but display block is constant.i want to it's value be dynamic. thanks for attention