The second project involves completing and extending the C++ program that evalua
ID: 3857467 • Letter: T
Question
The second project involves completing and extending the C++ program that evaluates statements of an expression language contained in the module 3 case study. The statements of that expression language consist of an arithmetic expression followed by a list of assignments. Assignments are separated from the expression and each other by commas. A semicolon terminates the expression. The arithmetic expressions are fully parenthesized infix expressions containing integer literals and variables. The valid arithmetic operators are +, –, *, /. Tokens can be separated by any number of spaces. Variable names begin with an alphabetic character, followed by any number of alphanumeric characters. Variable names are case sensitive. This syntax is described by BNF and regular expressions in the case study. The program reads in the arithmetic expression and encodes the expression as a binary tree. After the expression has been read in, the variable assignments are read in and the variables and their values of the variables are placed into the symbol table. Finally the expression is evaluated recursively. Your first task is to complete the program provided by providing the three missing classes, Minus, Times and Divide. Next, you should extend the program so that it supports relational, logical and conditional expression operators as defined by the following extension to the grammar: -> '(' ')' | '(' ':' '?' ')' | '(' '!' ')' -> '+' | '-' | '*' | '/' | '>' | '<' | '=' | '&' | '|' Note that there are a few differences in the use of these operators compared to their customary use in the C family of languages. Their differences are: In the conditional expression operator, the symbols are reversed and the third operand represents the condition. The first operand is the value when true and the second the value when false The logical operators use single symbols not double, for example the and operator is & not && The negation operator ! is a postfix operator, not a prefix one There are only three relational operators not the usual six and the operator for equality is = not == Like C and C++, any arithmetic expression can be interpreted as a logical value, taking 0 as false and anything else as true Your final task is to make the following two modifications to the program: The program should accept input from a file, allowing for multiple expressions arranged one per line.
Explanation / Answer
first case
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/*
* Test arithmetic operations
*/
#include <iostream>
using namespace std;
int main() {
int number1, number2; // Declare 2 integer variable number1 and number2
int sum, difference, product, quotient, remainder; // declare 5 int variables
// Prompt user for the two numbers
cout << "Enter two integers (separated by space): ";
cin >> number1 >> number2;
// Do arithmetic Operations
sum = number1 + number2;
difference = number1 - number2;
product = number1 * number2;
quotient = number1 / number2;
remainder = number1 % number2;
cout << "The sum, difference, product, quotient and remainder of "
<< number1 << " and " << number2 << " are "
<< sum << ", "
<< difference << ", "
<< product << ", "
<< quotient << ", and "
<< remainder << endl;
// Increment and Decrement
++number1; // Increment the value stored in variable number1 by 1
// same as "number1 = number1 + 1"
--number2; // Decrement the value stored in variable number2 by 1
// same as "number2 = number2 - 1"
cout << "number1 after increment is " << number1 << endl;
cout << "number2 after decrement is " << number2 << endl;
quotient = number1 / number2;
cout << "The new quotient of " << number1 << " and " << number2
<< " is " << quotient << endl;
return 0;
}
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output
Enter two integers: 98 5
The sum, difference, product, quotient and remainder of 98 and 5 are 103, 93, 49
0, 19, and 3
number1 after increment is 99
number2 after decrement is 4
The new quotient of 99 and 4 is 24
second case:
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/*
* Convert temperature between Celsius and Fahrenheit
*/
#include <iostream>
using namespace std;
int main() {
double celsius, fahrenheit;
cout << "Enter the temperature in celsius: ";
cin >> celsius;
fahrenheit = celsius * 9.0 / 5.0 + 32.0;
cout << celsius << " degree C is " << fahrenheit << " degree F." << endl << endl;
cout << "Enter the temperature in fahrenheit: ";
cin >> fahrenheit;
celsius = (fahrenheit - 32.0) * 5.0 / 9.0;
cout << fahrenheit << " degree F is " << celsius << " degree C." << endl;
return 0;
}
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output
Enter the temperature in celsius: 37.2
37.2 degree C is 98.96 degree F.
Enter the temperature in fahrenheit: 100
100 degree F is 37.7778 degree C.