Program for evaluation of prefix expression using stack

Integer at evaluationprefix. EvaluationPrefix EvaluationPreFix. Assuming we are talking about java. That means you can push objects of any type onto this stack. It seems that you only want to store Integers - tell the compiler about that by using generics. When you have a String and want to convert it to an Integer , you need to parse it, for example using Integer. But you need to be aware that this method will throw a NumberFormatException if the String is not a number.

You will have to handle this exception, for example by catching it and printing a helpful error message. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Evaluate a prefix expression using stacks Ask Question.

Asked 4 years, 4 months ago. Active 4 years, 4 months ago. Viewed 2k times. I have to evaluate a prefix expression using stacks, I did it but I don't understand why the code doesn't work properly, it marks 2 bugs when I compile the code, they are: Exception in thread "main" java.

A computer cannot easily differentiate between operators and parentheses, so infix expressions are converted into postfix or prefix. The precedence of operators determines the order of evaluation in an expression. To evaluate infix expressions, we need two stacks operator and operand stack , and to evaluate postfix and prefix expressions, we need only one stack operand stack. With the end of this article, we now know different methods for expression evaluation using stack.

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About Us. Privacy Policy. Bug Bounty. Press Release. Career Camp. Captain Coder. Hire Talent. Campus Ninja. Table of Contents. Source: giphy. Pop ;. Push o1 - o2 ;. WriteLine evaluatePrefix exprsn ;. Push operand to Stack. To convert exprsn[j] to digit subtract. Operator encountered. Pop two elements from Stack. Use switch case to operate on o1.

This code is contributed by divyesh Push num ;. Write evaluatePrefix exprsn ;. Previous Maximum number of chocolates to be distributed equally among k students. Next setlinestyle function in C. Recommended Articles. Article Contributed By :. Sayan Mahapatra.