CHUỖI VÀ CÁC BÀI TOÁN TRÊN CHUỖI part 3 ppt

Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 23 if stack.index=0 then pops:=false else begin pops:=true; dt:=stack.data[stack.index]; dec(stack.index); end; end; { } Procedure WriteStack(stack:stackc); var i:integer; Begin For i:=0 to stack.index do write(stack.data[i]); End; { } procedure WriteState(ch:char;P:string; stack:stackc); Begin inc(step); write(step:3,' '); write(ch:5); write(p:20);{Hien thi tung buoc} write(' '); writestack(stack);{Hien thi tung buoc} writeln; if step mod 23=0 then Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 24 Begin write('Press enter to continue '); readln; end; End; { } Function Priority(Token:char):integer; Begin case Token of '(',')': Priority:=0; '-','+': Priority:=1; '*','/': Priority:=2; '^': Priority:=3; End; End; { } Procedure Init(var stack:stackc); Begin stack.index:=0; End; { } Procedure InitR(var stack:stackR); Begin stack.index:=0; End; { } function TheTop(var stack:stackc):char; Begin if stack.index=0 then Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 25 TheTop:=#0 else TheTop:=stack.data[stack.index]; End; { } function Empty(var stack:stackc):boolean; Begin if stack.index=0 then Empty:=true else Empty:=false; End; { } function EmptyR(var stack:stackR):boolean; Begin if stack.index=0 then EmptyR:=true else EmptyR:=false; End; { } function Push(var stack:stackc;dt:char):boolean; Begin if stack.index=max+1 then push:=false else Begin inc(stack.index); push:=true; Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 26 stack.data[stack.index]:=dt; end; End; { } function PushR(var stack:stackR;dt:Real):boolean; Begin if stack.index=max+1 then pushR:=false else Begin inc(stack.index); pushR:=true; stack.data[stack.index]:=dt; end; End; { } function Pop(var stack:stackc;var dt:char):boolean; Begin if stack.index=0 then Pop:=false else Begin Pop:=True; dt:=stack.data[stack.index]; dec(stack.index); End; End; { } function PopR(var stack:stackR;var dt:Real):boolean; Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 27 Begin if stack.index=0 then PopR:=false else Begin PopR:=True; dt:=stack.data[stack.index]; dec(stack.index); End; End; { } function DeleteBlank(s:string):string; var i,j:integer; Begin j:=0; i:=1; while i<=length(s) do Begin if s[i]<>' ' then Begin inc(j); s[j]:=s[i]; End; inc(i); End; delete(s,j+1,length(s)-j); DeleteBlank:=s; End; { } Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 28 function Polish(s:string; var p:string) :boolean; var i,j:integer; stack:stackc; ch:char; Begin Polish:=true; s:=DeleteBlank(s); s:=s+')'; init(stack); push(stack,'('); i:=1; p:=''; while not Empty(stack) do Begin if upcase(s[i]) in ['A' 'Z'] then Begin p:=p+upcase(s[i]); WriteState(s[i],p,stack); end else Begin if s[i]='(' then Begin Push(stack,s[i]); WriteState(s[i],p,stack); End else if s[i] =')' then Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 29 Begin pop(stack,ch); while ch<>'(' do Begin p:=p+ch; pop(stack,ch); End; WriteState(s[i],p,stack); End else if s[i] in ['-','+','/','*','^'] then Begin{Coi nhu la phep tinh} while (Priority(TheTop(stack))>=Priority(s[i])) do Begin pop(stack,ch); p:=p+ch; End; push(stack,s[i]); WriteState(s[i],p,stack); End else Begin Polish:=false; exit; End; End; inc(i); End; End; Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 30 { } function Value(s:string;var outValue:real):boolean; { } function Add(a,b:real):real; Begin Add:=a+b; End; { } Function Sub(a,b:real):real; Begin Sub:=a-b; End; { } Function Mul(a,b:real):real; Begin Mul:=a*b; End; { } Function Divi(a,b:real; var c:real):boolean; Begin if b=0 then Divi:=false else Begin Divi:=true; c:=a/b; End; End; { } Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 31 Function expl(a,b:real;Var c:real):boolean; var temp:real; Begin if a<=0 then expl:=false else Begin expl:=true; c:=exp(b*ln(a)); End; End; { } type values=record exist:boolean; value:real; end; var temp,temp2,t:real; a:array['A' 'Z'] of values; i:integer; ch:char; stack:stackR; Check:boolean; {Main of value} Begin For ch:='A' to 'Z' do a[ch].exist:=false; for i:=1 to length(s) do if s[i] in ['A' 'Z'] then a[s[i]].exist:=true; Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 32 for Ch:= 'A' to 'Z' do if a[ch].exist= true then Begin write('Nhap gia tri cho bien ',ch,':'); readln(a[ch].value); End; s:=s+')'; i:=1; initR(stack); while(s[i]<>')') do Begin if upcase(s[i]) in ['A' 'Z'] then Begin pushR(stack,a[s[i]].Value); End; if s[i] in ['-','+','/','*','^'] then Begin popR(stack,temp); popR(stack,temp2); Check:=true; case s[i] of '-':t:=Sub(temp,temp2); '+':t:=Add(temp,temp2); '*':t:=mul(temp,temp2); '/':check:=divi(temp,temp2,t); '^':check:=expl(temp,temp2,t); end; if check=false then Begin [...]... i:=1 to dd-length(s) do s:=s+' '; end; { } Procedure taonen; {tao nen} var i:integer; begin textbackground(15); for i:=1 to 50 do Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 33 . inc(step); write(step :3, ' '); write(ch:5); write(p:20);{Hien thi tung buoc} write(' '); writestack(stack);{Hien thi tung buoc} writeln; if step mod 23= 0 then Vâ Minh. '^':check:=expl(temp,temp2,t); end; if check=false then Begin Vâ Minh Phæ – Bæ m«n Khoa häc m¸y tÝnh 33 value:=false; exit; end else Begin pushR(stack,t); End; End; inc(i); End;. '-','+': Priority:=1; '*','/': Priority:=2; '^': Priority: =3; End; End; { } Procedure Init(var stack:stackc); Begin stack.index:=0; End; { } Procedure