infix to postfix negation
Hello there,
I am trying to make a calculator program. But I have a problem with the negative sign. I fixed the program to do expression of (05)+12 if I want 5 to be negative. But I want and I am expecting it to do something like 5+12 .Please help...Thank you in advance EXAMPLE OUTPUT : Code:
Enter an infix expression: Code:
Enter an infix expression: Code:
case '': so that in converting infix to postfix Code:
case UNARY: case '': else if ('' == UNARY) // unary operator { //push2(pop2() * (01)); push2(pop2() * 1); } 
Re: infix to postfix negation
Well it's OK to post odd segments of the code but really we can't solve it from that. You have to post the whole thing. The solution is probably to extend your definition of a number: where you are expecting 09, you must also expect a possible '', and it is the context that will define whether that means subtract or minus. So 5+12 would see the  as negative rather than subtract, because at that point it is expecting a number. But 12+5 would also see the  as a negative because it's already seen an operator so is now expecting a number. On the other hand 125 would see the  as subtract, because it is looking for an operator, and programmed correctly your program shouldn't be confused by 125 which would be interpreted as 12 minus (5).

Re: infix to postfix negation
Thank you but I'm still confused, from your explanation does it mean that I will make negative as part of the operand? i.e. 1+ 12 , push the whole 12?

Re: infix to postfix negation
Yes of course. 12: the  is an essential part of the number. It's what makes it a negative number.

Re: infix to postfix negation
Is it like this? I put it this way but it didn't work.
Code:
case '': 
Re: infix to postfix negation
No idea, can't solve it from fragmented sections of code.

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