例题：从键盘上输入三个数，对它们进行比较，判断出谁最大，并将结果显示在屏幕上。

解法一：

program bj(input,output);
var x,y,z,a:real;
begin
write('please input 3 numbers:');
read(x,y,z);
if x>=y then
a:=x
else
a:=y;
if a>=z then
write('the biggest number is:',a:8:2)
else
write('the biggest number is:',z:8:2);
end.

解法二：

program bijiao(input,output);
var x,y,z:real;
begin
write('input 3 numbers:');
read(x,y,z);
if (x>=y)and(x>z) then
write('the biggest number is:',x:8:2);
if (y>x)and(y>=z) then
write('the biggest number is:',y:8:2);
if (z>=x)and(z>y) then
write('the biggest number is:',z:8:2);
if (x=y)and(x=z) then
write('the biggest number is:',x:8:2);
end.