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this web app is a simple calculator that adds and subtracts. my problem is that the add and the subtract buttons don't work
i get the following errors : "18 in the jsp file: /adder.jsp opchar cannot be resolved " and "An error occurred at line: 52 in the jsp file: /adder.jsp opchar cannot be resolved" i know i need to initialize opchar but dont know how
#1 don't put java code in a jsp. Java code belongs in a java class.
#2 Unless you're using java 7, you can't switch on a String.
#3 You can't compare strings with ==. Use the equals() method.
#4 The subtraction operator is '-', not '+'
To initialize opchar you need to declare the variable, and give it a value.
Depending upon which button you clicked in your form, the value of opchar would then be either 'add' or 'subtract'