输入四个字母,按字母表顺序从小到大输出这四个字母?(PASCAL语言编写)

Answer 1

var a,k:array[1..4]of char;i,j:longint;
begin
for i:=1 to 4 do
begin
write('a[',i,']=');readln(a[i]);
end;
for i:=1 to 4 do
for j:=i to 4 do
begin
if ord(a[j])<=ord(a[i])then
begin
k[j]:=a[j];
a[j]:=a[i];
a[i]:=k[j];
end;
end;
for i:=1 to 4 do
begin
write(a[i]);
if i<4 then write(',');
end;
readln
end.

Answer 2

var i,j:longint;
s:string;
a:array[1..4] of string;

procedure swap(x,y:longint);
var tmp:string;
begin
tmp:=a[x];
a[x]:=a[y];
a[y]:=tmp;
end;

begin
readln(s);
for i:=1 to 4 do a[i]:=copy(s,i,1);
for i:=1 to 3 do
for j:=i+1 to 4 do
if a[i]>a[j] then swap(i,j);
for i:=1 to 4 do write(a[i]);
writeln;
end.