int main()
{
//declare objects of stack
STACK<char, 100> P;
char SENT;
P.MakeStack();
//collect the sentence
cout << "Please, type a sentence: "; cin.get(SENT); //read first character
//collect the sentence a character at a time
while( SENT!='\n' )
{
if( isalpha(SENT) )
P.PushStack(SENT);
cin.get(SENT); //get next character
}
//display sentence in reverse (*reverse is normal in stack*)
while( !P.EmptyStack()!='\0' )
cout<<P.PopStack();
cout<<endl;
//end program
system("PAUSE");
return 0;
}
int main()
{
char con;
do
{
char num[20]; int count = 0; string out; int OperatorCount = 0; int ParenNumCount = 0;
STACK <char, 20> loadNum; STACK <char, 20> loadOperator; STACK <char, 20> flipStack; STACK <char, 20> FlipOperator;
cout << "Enter an infix expression:";
cin.getline(num,20);
loadNum.ClearStack(); loadOperator.ClearStack(); flipStack.ClearStack(); FlipOperator.ClearStack();
NumCheck: while (num[count] != '$')
{
if (num[count] == '(')
{
count++;
while (num[count] != ')')
{
if (isalpha(num[count]))
{
loadNum.PushStack(num[count]);
count++; ParenNumCount++;
}
else if (num[count] == '*' || num[count] == '+' || num[count] == '-' || num[count] == '/')
{
loadOperator.PushStack(num[count]);
count++; OperatorCount++;
}
}
count++;
goto NumCheck;
}
if (isalpha(num[count]))
{
loadNum.PushStack(num[count]);
count++;
goto NumCheck;
}
if (num[count] == '*' || num[count] == '+' || num[count] == '-' || num[count] == '/')
{
loadOperator.PushStack(num[count]);
count++;
OperatorCount++;
}
if (num[count] == '$') { goto NumCheck; }
}
//flip
while (!loadNum.EmptyStack())
{
flipStack.PushStack(loadNum.PopStack());
}
while (!loadOperator.EmptyStack())
{
FlipOperator.PushStack(loadOperator.PopStack());
}
count = 0;
//output
if (ParenNumCount % 2 == 0)
{
while (!flipStack.EmptyStack())
{
if (count % 2 == 0)
{
out += flipStack.PopStack();
out += flipStack.PopStack();
if (OperatorCount >= 0)
{
out += FlipOperator.PopStack();
OperatorCount--;
}
count++;
}
else
{
out += flipStack.PopStack();
if (OperatorCount >= 0)
{
out += FlipOperator.PopStack();
OperatorCount--;
}
}
}
}
else if (ParenNumCount % 2 != 0)
{
while (!flipStack.EmptyStack())
{
out += flipStack.PopStack();
}
while (!FlipOperator.EmptyStack())
{
out += FlipOperator.PopStack();
}
}
cout << "Postfix form of the expression is:" << out << endl; cout << "Continue y/n:"; cin >> con; cin.ignore();
} while (con != 'n');
system("pause");
return 0;
}
