add toPostfix function(in stackApp.cpp). Create Queue.h, and passed all tests.

thu_dsa/chp4/Queue.h

@@ -0,0 +1,15 @@
+#ifndef QUEUE_H_
+#define QUEUE_H_
+
+#include "../chp3/List.h"
+
+template <typename T>
+class Queue: public List<T>{
+public:
+	void enqueue(T const &elem) { push_back(elem); }
+	T dequeue() { return  pop_front()->val; }
+	T front() { return first()->val; }
+	T rear() { return last()->val; }
+};
+
+#endif

thu_dsa/chp4/stackApp.cpp

@@ -1,5 +1,6 @@
 #include "../chp2/Fib.h"
 #include "stackApp.h"
+#include <stdlib.h>
 #include <string>
 
 /*-----------build-in functions----------*/
@@ -9,6 +10,7 @@ inline char orderBetween(char optr1, char optr2);
 int findOptr(char optr);
 double cal(char optr, double opnd);
 double cal(double opnd1, char optr, double opnd2);
+void append(char* &des, char c);
 
 /*
  * @brief : convert a decimal digit n to any base(2 <= base <= 36)
@@ -106,6 +108,42 @@ double evaluate(char* infixExpr){
 	return opnd.pop();
 }
 
+/*
+ * @brief : to convert an infix expression to a postfix one
+ * @args  : infixExpr
+ * @return: return the converted postfix expression
+ * @others: only consider valid infix expression
+ */
+char* toPostfix(char* infixExpr){
+	char* postfixExpr = "";
+	Stack<char> optr;
+	optr.push('\0');
+	while(!optr.empty()){
+		if (isdigit(*infixExpr)) append(postfixExpr, *infixExpr++);
+		else{
+			if (*infixExpr == ' ' || *infixExpr == '\t') { // skip white spaces
+				++infixExpr;
+				continue;
+			}
+			switch(orderBetween(optr.top(), *infixExpr)){
+			case '>':
+				append(postfixExpr, optr.pop());
+				break;
+
+			case '<':
+				optr.push(*infixExpr++);
+				break;
+
+			case '=':
+				optr.pop();
+				++infixExpr;
+				break;
+			}
+		}
+	}
+	return postfixExpr;
+}
+
 /*-----------build-in functions----------*/
 int readNumber(char* &expr){
 	int res = 0;
@@ -178,3 +216,16 @@ double cal(double opnd1, char optr, double opnd2) {
 	}
 	return res;
 }
+
+/*
+ * @brief : to append a char to an array of char, even if the array is already full
+ * @args  : char* des, char c
+ * @return: void
+ * @others: the array can automatically expand itself when needed
+ */
+void append(char* &des, char c){
+	int n = strlen(des);
+	char* tmp = des;
+	des = new char[n + 2];
+	sprintf(des, "%s%c\0", tmp, c);
+}

thu_dsa/chp4/stackApp.h

@@ -6,9 +6,9 @@
 #define NOPTR 9
 
 static char digits[] = { '0','1','2','3','4','5','6','7','8','9',
-						'a','b','c','d','e','f','g','h','i','j',
-						'k','l','m','n','o','p','q','r','s','t',
-						'u','v','w','x','y','z' };
+						 'a','b','c','d','e','f','g','h','i','j',
+					 	 'k','l','m','n','o','p','q','r','s','t',
+						 'u','v','w','x','y','z' };
 /*
  * @brief : convert a decimal digit n to any base(2 <= base <= 36)
  * @args  : 
@@ -44,4 +44,12 @@ const char pri[NOPTR][NOPTR] = {
  */
 double evaluate(char* infixExpr);
 
+/*
+ * @brief : to convert an infix expression to a postfix one
+ * @args  : infixExpr
+ * @return: return the converted postfix expression
+ * @others: only consider valid infix expression
+ */
+char* toPostfix(char* infixExpr);
+
 #endif

thu_dsa/chp4/testQueue.cpp

@@ -0,0 +1,61 @@
+#include "Queue.h"
+#include <time.h>
+#include <cassert>
+#include <iostream>
+using std::cout;
+using std::endl;
+
+void test_constructor();
+void test_enqueue();
+void test_dequeue();
+
+int main(){
+	clock_t begin = clock();
+	cout << "Running tests." << endl;
+
+	test_constructor();
+	test_enqueue();
+	test_dequeue();
+
+	clock_t end = clock();
+	cout << "All tests passed." << "Running time: " << end - begin << "ticks." << endl;
+
+	system("pause");
+	return 0;
+}
+
+void test_constructor(){
+	Queue<int> q1;
+	Queue<char> q2;
+	Queue<double> q3;
+	Queue < Queue<int>> q4;
+	assert(q1.getSize() == 0);
+	assert(q2.getSize() == 0);
+	assert(q3.getSize() == 0);
+	assert(q4.getSize() == 0);
+}
+
+void test_enqueue(){
+	Queue<int> q;
+	q.enqueue(2);
+	assert(q.getSize() == 1);
+	q.enqueue(5);
+	assert(q.getSize() == 2);
+	assert(q.front() == 2);
+	assert(q.rear() == 5);
+}
+
+void test_dequeue(){
+	Queue<int> q;
+	q.enqueue(2);
+	q.enqueue(5);
+	q.enqueue(7);
+	assert(q.getSize() == 3);
+	assert(q.front() == 2);
+	assert(q.rear() == 7);
+
+	assert(q.dequeue() == 2);
+	assert(q.dequeue() == 5);
+	assert(q.dequeue() == 7);
+	assert(q.getSize() == 0);
+}

thu_dsa/chp4/testStackApp.cpp

@@ -9,12 +9,14 @@ using std::endl;
 void test_convert();
 void test_paren();
 void test_evaluate();
+void test_toPostfix();
 
-int main(){
+int stackApp_test_main(){
 	cout << "Running tests......" << endl;
 	test_convert();
 	test_paren();
 	test_evaluate();
+	test_toPostfix();
 	
 	cout << "All tests passed." << endl;
 	system("pause");
@@ -38,3 +40,7 @@ void test_evaluate(){
 	assert(evaluate("2*5+(3+4-2*7)/2") == 6.5);
 	assert(evaluate("(0!+ 1) * 2 ^ (3!+ 4) - (5!- 67 - (8 + 9))") == 2012);
 }
+
+void test_toPostfix(){
+	assert(strcmp(toPostfix("(0! + 1) ^ (2 * 3! + 4 - 5)"),"0!1+23!*4+5-^") == 0);
+}