algorithms/Java/InfixtoPostfix.java at master · AASF-IIITM/algorithms · GitHub

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importjava.util.Stack;

classTest
{

staticintPrec(charch)
	{
switch (ch)
 {
case'+':
case'-':
return1;

case'*':
case'/':
return2;

case'^':
return3;
 }
return -1;
	}


staticStringinfixToPostfix(Stringexp)
	{

Stringresult = newString("");


Stack<Character> stack = newStack<>();

for (inti = 0; i<exp.length(); ++i)
 {
charc = exp.charAt(i);


if (Character.isLetterOrDigit(c))
result += c;


elseif (c == '(')
stack.push(c);

elseif (c == ')')
 {
while (!stack.isEmpty() && stack.peek() != '(')
result += stack.pop();

if (!stack.isEmpty() && stack.peek() != '(')
return"Invalid Expression"; // invalid expression
else
stack.pop();
 }
else// an operator is encountered
 {
while (!stack.isEmpty() && Prec(c) <= Prec(stack.peek())){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
stack.push(c);
 }

 }


while (!stack.isEmpty()){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
returnresult;
	}

publicstaticvoidmain(String[] args)
	{
Stringexp = "a+b*(c^d-e)^(f+g*h)-i";
System.out.println(infixToPostfix(exp));
	}
}
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importjava.util.Stack;

classTest
{

staticintPrec(charch)
	{
switch (ch)
 {
case'+':
case'-':
return1;

case'*':
case'/':
return2;

case'^':
return3;
 }
return -1;
	}


staticStringinfixToPostfix(Stringexp)
	{

Stringresult = newString("");


Stack<Character> stack = newStack<>();

for (inti = 0; i<exp.length(); ++i)
 {
charc = exp.charAt(i);


if (Character.isLetterOrDigit(c))
result += c;


elseif (c == '(')
stack.push(c);

elseif (c == ')')
 {
while (!stack.isEmpty() && stack.peek() != '(')
result += stack.pop();

if (!stack.isEmpty() && stack.peek() != '(')
return"Invalid Expression"; // invalid expression
else
stack.pop();
 }
else// an operator is encountered
 {
while (!stack.isEmpty() && Prec(c) <= Prec(stack.peek())){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
stack.push(c);
 }

 }


while (!stack.isEmpty()){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
returnresult;
	}

publicstaticvoidmain(String[] args)
	{
Stringexp = "a+b*(c^d-e)^(f+g*h)-i";
System.out.println(infixToPostfix(exp));
	}
}
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importjava.util.Stack;

classTest
{

staticintPrec(charch)
	{
switch (ch)
 {
case'+':
case'-':
return1;

case'*':
case'/':
return2;

case'^':
return3;
 }
return -1;
	}


staticStringinfixToPostfix(Stringexp)
	{

Stringresult = newString("");


Stack<Character> stack = newStack<>();

for (inti = 0; i<exp.length(); ++i)
 {
charc = exp.charAt(i);


if (Character.isLetterOrDigit(c))
result += c;


elseif (c == '(')
stack.push(c);

elseif (c == ')')
 {
while (!stack.isEmpty() && stack.peek() != '(')
result += stack.pop();

if (!stack.isEmpty() && stack.peek() != '(')
return"Invalid Expression"; // invalid expression
else
stack.pop();
 }
else// an operator is encountered
 {
while (!stack.isEmpty() && Prec(c) <= Prec(stack.peek())){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
stack.push(c);
 }

 }


while (!stack.isEmpty()){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
returnresult;
	}

publicstaticvoidmain(String[] args)
	{
Stringexp = "a+b*(c^d-e)^(f+g*h)-i";
System.out.println(infixToPostfix(exp));
	}
}
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importjava.util.Stack;

classTest
{

staticintPrec(charch)
	{
switch (ch)
 {
case'+':
case'-':
return1;

case'*':
case'/':
return2;

case'^':
return3;
 }
return -1;
	}


staticStringinfixToPostfix(Stringexp)
	{

Stringresult = newString("");


Stack<Character> stack = newStack<>();

for (inti = 0; i<exp.length(); ++i)
 {
charc = exp.charAt(i);


if (Character.isLetterOrDigit(c))
result += c;


elseif (c == '(')
stack.push(c);

elseif (c == ')')
 {
while (!stack.isEmpty() && stack.peek() != '(')
result += stack.pop();

if (!stack.isEmpty() && stack.peek() != '(')
return"Invalid Expression"; // invalid expression
else
stack.pop();
 }
else// an operator is encountered
 {
while (!stack.isEmpty() && Prec(c) <= Prec(stack.peek())){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
stack.push(c);
 }

 }


while (!stack.isEmpty()){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
returnresult;
	}

publicstaticvoidmain(String[] args)
	{
Stringexp = "a+b*(c^d-e)^(f+g*h)-i";
System.out.println(infixToPostfix(exp));
	}
}
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importjava.util.Stack;

classTest
{

staticintPrec(charch)
	{
switch (ch)
 {
case'+':
case'-':
return1;

case'*':
case'/':
return2;

case'^':
return3;
 }
return -1;
	}


staticStringinfixToPostfix(Stringexp)
	{

Stringresult = newString("");


Stack<Character> stack = newStack<>();

for (inti = 0; i<exp.length(); ++i)
 {
charc = exp.charAt(i);


if (Character.isLetterOrDigit(c))
result += c;


elseif (c == '(')
stack.push(c);

elseif (c == ')')
 {
while (!stack.isEmpty() && stack.peek() != '(')
result += stack.pop();

if (!stack.isEmpty() && stack.peek() != '(')
return"Invalid Expression"; // invalid expression
else
stack.pop();
 }
else// an operator is encountered
 {
while (!stack.isEmpty() && Prec(c) <= Prec(stack.peek())){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
stack.push(c);
 }

 }


while (!stack.isEmpty()){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
returnresult;
	}

publicstaticvoidmain(String[] args)
	{
Stringexp = "a+b*(c^d-e)^(f+g*h)-i";
System.out.println(infixToPostfix(exp));
	}
}
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importjava.util.Stack;

classTest
{

staticintPrec(charch)
	{
switch (ch)
 {
case'+':
case'-':
return1;

case'*':
case'/':
return2;

case'^':
return3;
 }
return -1;
	}


staticStringinfixToPostfix(Stringexp)
	{

Stringresult = newString("");


Stack<Character> stack = newStack<>();

for (inti = 0; i<exp.length(); ++i)
 {
charc = exp.charAt(i);


if (Character.isLetterOrDigit(c))
result += c;


elseif (c == '(')
stack.push(c);

elseif (c == ')')
 {
while (!stack.isEmpty() && stack.peek() != '(')
result += stack.pop();

if (!stack.isEmpty() && stack.peek() != '(')
return"Invalid Expression"; // invalid expression
else
stack.pop();
 }
else// an operator is encountered
 {
while (!stack.isEmpty() && Prec(c) <= Prec(stack.peek())){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
stack.push(c);
 }

 }


while (!stack.isEmpty()){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
returnresult;
	}

publicstaticvoidmain(String[] args)
	{
Stringexp = "a+b*(c^d-e)^(f+g*h)-i";
System.out.println(infixToPostfix(exp));
	}
}
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76
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78
79
80
81
importjava.util.Stack;

classTest
{

staticintPrec(charch)
	{
switch (ch)
 {
case'+':
case'-':
return1;

case'*':
case'/':
return2;

case'^':
return3;
 }
return -1;
	}


staticStringinfixToPostfix(Stringexp)
	{

Stringresult = newString("");


Stack<Character> stack = newStack<>();

for (inti = 0; i<exp.length(); ++i)
 {
charc = exp.charAt(i);


if (Character.isLetterOrDigit(c))
result += c;


elseif (c == '(')
stack.push(c);

elseif (c == ')')
 {
while (!stack.isEmpty() && stack.peek() != '(')
result += stack.pop();

if (!stack.isEmpty() && stack.peek() != '(')
return"Invalid Expression"; // invalid expression
else
stack.pop();
 }
else// an operator is encountered
 {
while (!stack.isEmpty() && Prec(c) <= Prec(stack.peek())){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
stack.push(c);
 }

 }


while (!stack.isEmpty()){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
returnresult;
	}

publicstaticvoidmain(String[] args)
	{
Stringexp = "a+b*(c^d-e)^(f+g*h)-i";
System.out.println(infixToPostfix(exp));
	}
}
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importjava.util.Stack;

classTest
{

staticintPrec(charch)
	{
switch (ch)
 {
case'+':
case'-':
return1;

case'*':
case'/':
return2;

case'^':
return3;
 }
return -1;
	}


staticStringinfixToPostfix(Stringexp)
	{

Stringresult = newString("");


Stack<Character> stack = newStack<>();

for (inti = 0; i<exp.length(); ++i)
 {
charc = exp.charAt(i);


if (Character.isLetterOrDigit(c))
result += c;


elseif (c == '(')
stack.push(c);

elseif (c == ')')
 {
while (!stack.isEmpty() && stack.peek() != '(')
result += stack.pop();

if (!stack.isEmpty() && stack.peek() != '(')
return"Invalid Expression"; // invalid expression
else
stack.pop();
 }
else// an operator is encountered
 {
while (!stack.isEmpty() && Prec(c) <= Prec(stack.peek())){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
stack.push(c);
 }

 }


while (!stack.isEmpty()){
if(stack.peek() == '(')
return"Invalid Expression";
result += stack.pop();
 }
returnresult;
	}

publicstaticvoidmain(String[] args)
	{
Stringexp = "a+b*(c^d-e)^(f+g*h)-i";
System.out.println(infixToPostfix(exp));
	}
}