Calc by ratneshkatiyar · Pull Request #9 · alexkutsan/dummy_project

ratneshkatiyar · 2020-07-17T08:57:26Z

No description provided.

alexkutsan · 2020-07-20T07:09:07Z

test/calculator_test.cpp

+        {
+            EXPECT_EQ(7.8, project_.calc("5.5 2.3 +"));
+        }
+        TEST_F(CalculatorTest, MissingOperand)


Negative and positive test cases.

alexkutsan · 2020-07-20T07:09:28Z

test/calculator_test.cpp

+        }
+        TEST_F(CalculatorTest, MissingOperand)
+        {
+            EXPECT_EQ(-1, project_.calc("5 +"));


Check a way to handle errors

alexkutsan · 2020-07-27T09:57:51Z

polishNotationCalc.cpp

        if (str.size() == 0)
-            return 0;
+            throw Exception{"Nothing to work on as Input is empty"};
        for (int i = 0; i < str.size(); i++)


is it possible to use iterator or range based loop?

alexkutsan · 2020-07-27T09:58:35Z

polishNotationCalc.cpp

-                // {
-                //     std::cout << "calc::Exception" << e.what();
-                // }
+                res = performOperation(str[i], operandVal.first, operandVal.second);


Next step is to separate parsing and evaluating

alexkutsan · 2020-07-27T09:59:53Z

polishNotationCalc.cpp

        return mStack.top();
    }
+
+    void PolishCalc::pushOperandInStack(const std::string &str, int &curr_pos)


mark variable as output explicit with name curr_pos_out

return new position

alexkutsan · 2020-07-27T10:00:44Z

polishNotationCalc.cpp

+    {
+        double secOperand = 0;
+        double firstOperand = 0;
+        if (mStack.size() >= 2)


swap if condition and make early return/ throw ( safety check)

LuxoftAKutsan · 2020-07-28T08:12:59Z

polishNotationCalc.hpp

+        void pushOperandInStack(const std::string &, int &curr_pos);
+        std::pair<double, double> getOperandFromStack();
        std::stack<double> mStack;
+        std::map<const char, functionCall> mMap;


mMap bad name. Try to avoid put type name in variable, Show business value of variable

LuxoftAKutsan · 2020-07-28T08:13:42Z

polishNotationCalc.hpp

-        double performOperation(const char operation, const double firstOperand, const double secOperand);
-        void pushOperandInStack(const std::string &, int& curr_pos);
-        std::pair<double,double> getOperandFromStack();
+        void insertFunctionInsideMap();


Try to use constexpr for this.

LuxoftAKutsan · 2020-07-28T08:15:40Z

polishNotationCalc.cpp

                auto operandVal = getOperandFromStack();
                double res = 0;
-                res = performOperation(str[i], operandVal.first, operandVal.second);
+                res = mMap[str[i]](operandVal.first, operandVal.second);


extract variable for str[i]

suggest to split implementation to parsing, validating and calculating steps

LuxoftAKutsan · 2020-07-28T08:17:42Z

polishNotationCalc.cpp

+        mMap.insert(std::make_pair('-', [](double a, double b) { return a - b; }));
+        mMap.insert(std::make_pair('*', [](double a, double b) { return a * b; }));
+        mMap.insert(std::make_pair('/', [](double a, double b) { 
+            if(b==0)


LuxoftAKutsan · 2020-07-28T08:19:52Z

polishNotationCalc.cpp

+    {
+        mMap.insert(std::make_pair('+', [](double a, double b) { return a + b; }));
+        mMap.insert(std::make_pair('-', [](double a, double b) { return a - b; }));
+        mMap.insert(std::make_pair('*', [](double a, double b) { return a * b; }));


use const as wide as you cat

LuxoftAKutsan · 2020-07-29T07:06:54Z

polishNotationCalc.cpp

+            throw Exception{"Nothing to work on as Input is empty"};
+        for (int i = 0; i < str.size(); i++)
+        {
+            if (str[i] == ' ')


avoid missing brackets even in one line if/else/while ...

LuxoftAKutsan · 2020-07-29T07:12:57Z

polishNotationCalc.cpp

+        return false;
+    }
+
+    double PolishCalc::calc( const std::string &str)


3 blocks :

1. Basic Validation // Check that the is not bad symbols and so on 2. Parsing // Use not strings, but OOP types or lambdas for futher working 2.1 Validation : count of operator matches count of operands 3. Calculation // Evaluete expression

2 stacks :
Validation block fill up 2 stacks :

Operator stack

Operand stack

Calculation should work with Operator/Operand or lambda types but not string.

LuxoftAKutsan · 2020-07-29T07:13:58Z

polishNotationCalc.cpp

+        {
+            if (str[i] == ' ')
+                continue;
+            if (isNumeric(str[i]))


Try to modify solution to work with negative numbers

LuxoftAKutsan · 2020-07-29T07:17:13Z

polishNotationCalc.cpp

+    {
+        double operand = 0;
+        std::string temp = "";
+        while (curr_pos < str.size() && !(str[curr_pos] == ' '))


In case of input like 2 4+ , solution behaviour is undefined.
Try to handle this error.
Best option is to create prevalidation function and contract for pushOperandInStack.

LuxoftAKutsan · 2020-07-29T07:18:17Z

polishNotationCalc.cpp

+                continue;
+            if (isNumeric(str[i]))
+            {
+                pushOperandInStack(str, i);


Try to work with some kind of tokens but not charters.
It is not obvious that pushOperandInStack will modify i variable. If it is possible. Try to avoid it

LuxoftAKutsan · 2020-07-29T07:20:27Z

polishNotationCalc.cpp

+                pushOperandInStack(str, i);
+
+            }
+            if (isOperator(str[i]))


Create separate loop to fill operator stack, operand stack an calculation based on 2 stacks

LuxoftAKutsan · 2020-07-29T07:21:07Z

polishNotationCalc.cpp

+            {
+                auto operandVal = getOperandFromStack();
+                double res = 0;
+                res = mOperatorMap[str[i]](operandVal.first, operandVal.second);


Move calculation to the third loop

LuxoftAKutsan · 2020-07-29T07:27:37Z

polishNotationCalc.cpp

+        if (num == '+' || num == '-' || num == '*' || num == '/')
+            return true;
+        return false;
+    }


for (from 0 to N) { Operation 1 Operation 2 Operation 3 }

for (from 0 to N) { Opertation 1 } for (from 0 to N) { Opertation 2 } for (from 0 to N) { Opertation 3 }

Both solutions have the same performance

LuxoftAKutsan · 2020-07-29T07:48:06Z

polishNotationCalc.cpp

+    {
+        insertFunctionInsideMap();
+    }
+


1 Step : Create Token stack and validate it

token_stack& = stack<Tocken> Token { // Process one tocken in the stack void process(token_stack& ) double value(const token_stack& ) << // Follow contant } NumericToken : Token { void process(token_stack& ) -> do nothing double value(token_stack& ) -> return value_ double value_ } OperatorTocken : Token { pair PopTockens } PlusTocken : OperatorTocken { void process(token_stack& ) { pop token from stack -> get value -> double res1 pop token2 from stack -> get value -> double res2 res1 + res2 -> Plus result Push plus result to token vector as Numeric } double value(const token_stack&) { // Option 1 Contract thet process() should be evaluated before value () return top of the token_stack& value() // Option 2 Base that there process() could not be called get token from stack -> get value -> double res1 get token2 from stack on the second position -> get value -> double res2 res1 + res2 -> Plus result return Plus result as double } }

3 step Go throw all tokens and call process to them

Calc unit test case

da3665e

ratneshkatiyar force-pushed the Calculator branch from f7c8c12 to da3665e Compare July 19, 2020 09:26

alexkutsan reviewed Jul 20, 2020

View reviewed changes

rkatiyar added 4 commits July 20, 2020 11:14

Implementation of polishCalc

1db6fc8

Add Exception class

a7fa1dd

Add const and value by reference

19a9b77

Refactoring: Add newfunction

a38c473

alexkutsan reviewed Jul 27, 2020

View reviewed changes

refactor: remove switch conditions

4dfa118

LuxoftAKutsan reviewed Jul 28, 2020

View reviewed changes

Add const and variable name change

6a5cc3d

LuxoftAKutsan reviewed Jul 29, 2020

View reviewed changes

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ratneshkatiyar commented Jul 17, 2020

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LuxoftAKutsan Jul 28, 2020 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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LuxoftAKutsan Jul 29, 2020 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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LuxoftAKutsan Jul 28, 2020 •

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LuxoftAKutsan Jul 29, 2020 •

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