Pascal-Lazarus Tutorial

ตัวอย่าง การส่ง function เข้าไปอีก function หนึ่ง
ข้อสังเกต: ปัญหาการส่งผ่าน func เข้าไปใน average_value ไม่สามารถทำได้

//define polynomial function f(x) = x^2+2*x-5
function func(x:real):real;
begin
  result:=x*x+2*x-5 ;
end;

//create function to find the average value between a and b of any function
function average_value(a,b:real):real;
begin
  result:=(a+b)/2;
end;
  

//Call the above function
BEGIN
  writeln(average_value(func(1),func(10))); //Error!!! 
  //cannot pass "func" as argument.

END.  

Type
  Tfunc = function(x:real):real; 

//define polynomial function f(x) = x^2+2*x-5
function func(x:real):real;
begin
  result:=x*x+2*x-5 ;
end;

//create function to find the average value between a and b of any function
function average_value(f:Tfunc; a,b:real):real;
begin
  result:=(f(a)+f(b))/2;
end;
  
//Call the above function
BEGIN
  writeln(average_value(@func,1,10)); 

END.  

Type
  Tfunc = function(x:real):real; 

//define polynomial function f(x) = x^2+2*x-5
function func(x:real):real;
begin
  result:=x*x+2*x-5 ;
end;

//create function to find the average value between a and b of any function
function average_value(f:Tfunc; a,b:real):real;
begin
  result:=(f(a)+f(b))/2;
end;
  
//Call the above function
BEGIN
  //Lazarus
  writeln(average_value(@func,1,10)); 
  
  //Delhpi
  writeln(average_value(func,1,10)); 

END.