Texas Instruments TINSPIRE Teacher Software Guidebook - Page 704

• A function can refer to any variable; however, it can store a value to a local variable only. Programs can store to local and global variables. Note: Arguments used to pass values to a function are treated as local variables automatically. If you want to store to any other variables, you must declare them as Local from within the function. • A function cannot call a program as a subroutine, but it can call another user-defined function. • You cannot define a program within a function. • A function cannot define a global function, but it can define a local function. Calling one program from another One program can call another program as a subroutine. The subroutine can be external (a separate program) or internal (included in the main program). Subroutines are useful when a program needs to repeat the same group of commands at several different places. Calling a separate program To call a separate program, use the same syntax that you use to run the program from the entry line. Define subtest1()= Prgm For i,1,4,1 subtest2(i,i¦1000) EndFor EndPrgm Define subtest2(x,y)= Prgm Disp x,y EndPrgm Defining and calling an internal subroutine To define an internal subroutine, use the Define command with Prgm...EndPrgm. Because a subroutine must be defined before it can be called, it is a good practice to define subroutines at the beginning of the main program. An internal subroutine is called and executed in the same way as a separate program. 692 Programming