125 lines
2 KiB
C
125 lines
2 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include<stdbool.h>
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#include<ctype.h>
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#include<string.h>
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#define MAX 100
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typedef struct TNode *Tptr;
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typedef struct TNode
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{
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char data;
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Tptr leftchild;
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Tptr rightchild;
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}TNode;
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///*
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//Create nodes in the tree
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Tptr createNode(char val)
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{
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Tptr temp =(Tptr)malloc(sizeof(TNode));
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temp->data = val;
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temp->leftchild = temp->rightchild = NULL;
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return temp;
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}
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//*/
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Tptr stack[MAX];
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int top=-1;
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int i;
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//check if stack is empty
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bool isEmpty()
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{
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return top==-1;
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}
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//check if stack is full
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bool isFull()
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{
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return top==MAX -1;
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}
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//push element onto stack
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void Push(Tptr e)
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{
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if(isFull())
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{
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return;
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}
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stack[++top]=e;
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}
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//pop element from stack
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Tptr Pop()
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{
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Tptr popped=createNode('\0');
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if(isEmpty())
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{
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free(popped);
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}
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else
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{
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popped=stack[top--];
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}
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return popped;
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}
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//check if character is operator
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bool isOperator(char ch)
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{
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bool ret=false;
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if(ch=='*' || ch=='/' || ch=='+' || ch=='-' || ch=='^' )
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{
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ret = true;
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}
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return ret;
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}
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Tptr createExpression(char* postfix)
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{
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int i;
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int plen =strlen(postfix);
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char cc;
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for(i=0;i<plen;i++)
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{
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cc = postfix[i];
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if(isalnum(cc))
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{
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Tptr node = createNode(cc);
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Push(node);
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}
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else if(isOperator(cc))
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{
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Tptr node = createNode(cc);
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node->rightchild = Pop();
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node->leftchild = Pop();
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Push(node);
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}
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}
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return stack[top];
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}
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void inOrderTraversal(Tptr root)
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{
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if (root != NULL)
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{
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inOrderTraversal(root->leftchild);
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printf("%c ", root->data);
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inOrderTraversal(root->rightchild);
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}
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}
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int main()
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{
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char postfix[] = "ab*cd/-";
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Tptr expressionTree = createExpression(postfix);
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if (expressionTree != NULL)
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{
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printf("In-Order Traversal of the Expression Tree: ");
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inOrderTraversal(expressionTree);
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printf("\n");
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}
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return 0;
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}
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