Thread: infix to postfix

  1. #1
    Registered User
    Join Date
    Jan 2002

    infix to postfix

    i have an string : (3+5) * (20/4)
    i have to convert this string to 3 5 + 20 4 / * (to postfix form)
    i cant do this can you tell me how can i do this

  2. #2
    Join Date
    Nov 2002
    Put the infix expression into a binary tree where the node is the operator and the left and right subtrees are what is being operated on.

    To convert this to postfix, use recursion

    postfix(tree T){

    if(leftsubtree == null && rightsubtree == null){
    print node;

    if(leftsubtree != null) postfix(leftsubtree);

    i(rightsubtree != null) postfix(rightsubtree);

    print node;


  3. #3
    Registered User
    Join Date
    Nov 2002
    There are a few references on the internet that do this. I wrote my own infix to postfix (in C not C++) and it used a stack which had values and operators pushed and popped off the stack is needed. The code may be a bit hard to read (I often don't comment my little ventures) but if you want it as a reference send me a PM.

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