程序如下:我想用integ过程调用标准的sin函数就不行,自己定义的就可以哟!
program integral(input,output);
type func=function(x:real):real;
function y(x:real):real;
begin
y:=1/(1+x);
end;
function sin1(x:real):real;
begin
sin1:=sin(x);
end;
procedure integ(operation:func
a,b:real;var inte:real);
const n=100;
var
s,w:real;
i:integer;
begin
w:=(b-a)/n;
s:=(operation(a)+operation(b))/2;
for i:=1 to n-1 do
s:=s+operation(a+i*w);
inte:=w*s;
end;
var a0,b0,inte0:real;
begin
writeln('Please input a and b:');
readln(a0,b0);
writeln('The following counts the integal of y=1/(1+x) from ');
writeln(a0:10:2,' to ',b0:10:2,':');
integ(y,a0,b0,inte0);
writeln('Throught method we get inte0=',inte0:10:2);
writeln('The following counts the integal of y=sin(x) from ',a0:10:2,' to ',b0:10:2,':');
{注意下面哟!}
integ(sin1,a0,b0,inte0);{此处将sin1改为sin就出错}
writeln('Throught method we get inte0=',inte0:10:2);
end.
