Introduction to BASIC   DEF statement

DEF statement
We use a DEF statement to define a function using an expression.
Example. 1

100 DEF f(x)=3*x^3-2*x^2+x
110 PRINT f(1),f(2),f(3)
120 END



Example. 2

10 DEF f(x)=3*x^3-2*x^2+x
20 FOR x=0 TO 10
30    PRINT f(x)
40 NEXT x
50 END


Example. 3 This has the same effect as Example. 2

10 DEF f(x)=3*x^3-2*x^2+x
20 FOR a=0 TO 10
30    PRINT f(a)
40 NEXT a
50 END


Example. 4

10 DEF f(x)=3*x^3-2*x^2+x
20 LET x=10
30 PRINT f(1)
40 PRINT x
50 END

x in the DEF line 10 and x in the lines 20 and 40 are distinct variables.
That is, when the line 30 is executed, the line 10 is executed to make x=1, but x in the lines 20 and 40 does not change.
Refer to DEF statement