; This function will not change the value of x value. ; increment and decrement operators will change value of variable ;Valdegg@ Solution (define (increment x) (+ 1 x) ) ; defining a variable var with initial value 3 (define var 3) (display (increment var)) (newline) (display var) (newline) ;uselpa@ answer (define-syntax incf (syntax-rules () ((_ x) (begin (set! x (+ x 1)) x)) ((_ x n) (begin (set! x (+ x n)) x)))) (define-syntax decf (syntax-rules () ((_ x) (incf x -1)) ((_ x n) (incf x (- n))))) (display (incf var)) (newline) (display var) (newline)