Question

Write a program that takes from standard input an expression without left parentheses and prints the equivalent infix expression with the parentheses inserted. For example, given the input: 1 + 2 ) * 3 - 4 ) * 5 - 6 ) ) ) your program should print ( ( 1 + 2 ) * ( ( 3 - 4 ) * ( 5 - 6 ) ) Without using imports for StdOut and StdIn and implementing your own Stack class

Answer 1

code:

public class _09_FixInfixExpression
{
  
public static void main(String[] args)
{
String s = "1 + 2 ) * 3 - 4 ) * 5 - 6 ) ) )";
Stack<Character> stack = new Stack<Character>();
for (int i = 0; i < s.length(); i++)
{
if (s.charAt(i) != ' ')
stack.push(s.charAt(i));
}
System.out.println();
s = fixInfix(stack);
System.out.println(s);
}

private static String fixInfix(Stack<Character> s)
{
Stack<Character> infix = new Stack<Character>();
Queue<String> numbers = new Queue<String>();
Stack<String> operators = new Stack<String>();
  
while (!s.isEmpty())
{
char c = s.pop();
if (c == ')')
{
infix.push(c);
}
else if (c == '-' || c == '+')
{
  
}
}
  
  
return infix.toString();
}

}