Data commit

Task/Parsing-RPN-to-infix-conversion/C/parsing-rpn-to-infix-conversion.c

@@ -0,0 +1,125 @@
+#include<stdlib.h>
+#include<string.h>
+#include<stdio.h>
+
+char** components;
+int counter = 0;
+
+typedef struct elem{
+	char data[10];
+	struct elem* left;
+	struct elem* right;
+}node;
+
+typedef node* tree;
+
+int precedenceCheck(char oper1,char oper2){
+	return (oper1==oper2)? 0:(oper1=='^')? 1:(oper2=='^')? 2:(oper1=='/')? 1:(oper2=='/')? 2:(oper1=='*')? 1:(oper2=='*')? 2:(oper1=='+')? 1:(oper2=='+')? 2:(oper1=='-')? 1:2;
+}
+
+int isOperator(char c){
+	return (c=='+'||c=='-'||c=='*'||c=='/'||c=='^');
+}
+
+void inorder(tree t){
+	if(t!=NULL){
+		if(t->left!=NULL && isOperator(t->left->data[0])==1 && (precedenceCheck(t->data[0],t->left->data[0])==1 || (precedenceCheck(t->data[0],t->left->data[0])==0 && t->data[0]=='^'))){
+			printf("(");
+			inorder(t->left);
+			printf(")");
+		}
+		else
+			inorder(t->left);
+	
+		printf(" %s ",t->data);
+	
+		if(t->right!=NULL && isOperator(t->right->data[0])==1 && (precedenceCheck(t->data[0],t->right->data[0])==1 || (precedenceCheck(t->data[0],t->right->data[0])==0 && t->data[0]!='^'))){
+			printf("(");
+			inorder(t->right);
+			printf(")");
+		}
+		else
+			inorder(t->right);
+	}
+}
+
+char* getNextString(){
+	if(counter<0){
+		printf("\nInvalid RPN !");
+		exit(0);
+	}
+	return components[counter--];
+}
+
+tree buildTree(char* obj,char* trace){
+	tree t = (tree)malloc(sizeof(node));
+	
+	strcpy(t->data,obj);
+	
+	t->right = (isOperator(obj[0])==1)?buildTree(getNextString(),trace):NULL;
+	t->left = (isOperator(obj[0])==1)?buildTree(getNextString(),trace):NULL;
+	
+	if(trace!=NULL){
+			printf("\n");
+			inorder(t);
+	}
+
+	return t;
+}
+
+int checkRPN(){
+	int i, operSum = 0, numberSum = 0;
+	
+	if(isOperator(components[counter][0])==0)
+		return 0;
+	
+	for(i=0;i<=counter;i++)
+		(isOperator(components[i][0])==1)?operSum++:numberSum++;
+
+	return (numberSum - operSum == 1);
+}
+
+void buildStack(char* str){
+	int i;
+	char* token;
+	
+	for(i=0;str[i]!=00;i++)
+		if(str[i]==' ')
+			counter++;
+		
+	components = (char**)malloc((counter + 1)*sizeof(char*));
+	
+	token = strtok(str," ");
+	
+	i = 0;
+	
+	while(token!=NULL){
+		components[i] = (char*)malloc(strlen(token)*sizeof(char));
+		strcpy(components[i],token);
+		token = strtok(NULL," ");
+		i++;
+	}
+}
+
+int main(int argC,char* argV[]){
+	int i;
+	tree t;
+	
+	if(argC==1)
+		printf("Usage : %s <RPN expression enclosed by quotes> <optional parameter to trace the build process>",argV[0]);
+	else{
+		buildStack(argV[1]);
+		
+		if(checkRPN()==0){
+			printf("\nInvalid RPN !");
+			return 0;
+		}
+		
+		t = buildTree(getNextString(),argV[2]);
+		
+		printf("\nFinal infix expression : ");
+		inorder(t);
+	}
+	
+	return 0;
+}