diff options
Diffstat (limited to 'Parser.java')
| -rw-r--r-- | Parser.java | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/Parser.java b/Parser.java index c588052..de41371 100644 --- a/Parser.java +++ b/Parser.java @@ -1,4 +1,6 @@ /* Todo +* - Fix this: +* when expression = 5+10*(10), it misses + * - Add support for trigonometric functions * - Remove all edge cases */ @@ -70,6 +72,9 @@ public class Parser { // Main Expression Iteration for (int i = 0; i < infix.length; i++) { char c = infix[i]; + + // Keep appending digits to the operand StringBuilder and skip iterations till + // we find a operator. if (isOperand(c)) { operand.append(infix[i]); if (i < infix.length - 1) { @@ -90,14 +95,22 @@ public class Parser { } operatorStack.pop(); } else { + // Manage precedence order of operatorStack operators while (!operatorStack.isEmpty() && getPresedence(c) <= getPresedence((char) operatorStack.peek()) && hasLeftAssociativity(c)) { output.add(operatorStack.pop().toString()); } - operatorStack.push(c); + + // For whatever reason, the last digit gets added to the operatorStack, leading + // to a duplicate of last digit in the expression + // To fix this, we again make sure that the current char is not a operand. + if (!isOperand(c)) { + operatorStack.push(c); + } } } + // pop all the operators left in the operatorStack after the loop is done. while (!operatorStack.isEmpty()) { if (operatorStack.peek() == '(') { return "This expression is invalid"; @@ -105,9 +118,7 @@ public class Parser { output.add(operatorStack.pop().toString()); } - // last digit gets duplicate entry for some reason, so have to remove it. - String op = output.toString(); - return op.substring(0, op.length() -2); + return output.toString(); } private Double evaluate(String operator, Double op1, Double op2) { |