C++ :: Expression Parser Implementation?
May 5, 2014How can we implement an expression parser in C++.
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C :: Program To Evaluate Postfix Expression Using Array Implementation Of Stack
Apr 26, 2014Write a program that evaluates postfix expression using array implementation of stack.
The expression [the input] is evaluated from left to right using a stack. When the element read from the expression is an operand, push it into the stack.When the element read from the expression is an operator: Pop two operands from the stack.Evaluate the two operandsPush the result of the evaluation into the stack.
The final result lies on the top of the stack at the end of the calculation. Make sure to display the result before terminating the program.Write a program that evaluates postfix expression using array implementation of stack.
Code:
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#define M 20
typedef struct{
[Code] ....
C :: Simple File Parser
Oct 5, 2013I am writing a simple file parser for use in another project (for config file). The trickiest thing seems to be skipping unwanted characters (comments, spaces). It works partly, but after the second line of an inputed file processes only the first three characters.
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define TEXT_FILE "data.txt"
[code]....
NOTE: Currently I am just trying to process and remove unwanted data, the actual processing of extracted data should be much simpler.
C/C++ :: Recursive Descent Parser?
Mar 22, 2014I am implementing a recursive descent parser that recognizes strings in the language below.
The grammar:
A -> I = E | E
E -> T + E | T - E | T
T -> F * T | F / T | F
F -> P ^ F | P
P -> I | L | UI | UL | (A)
U -> + | - | !
I -> C | CI
C -> a | b | ... | y | z
L -> D | DL
D -> 0 | 1 | ... | 8 | 9
My input file has the following two strings:
a=a+b-c*d
a=a**b++c
The desired output:
String read from file: a=a+b-c*d
The string "a=a+b-c*d" is in the language.
String read from file: a=a**b++c
The string "a=a**b++c" is not in the language.
[Code].....
When I test the code without reading the text file and just write a string in the source code, it appears to parse fine. I believe my main problem is in the int main function and how i am reading the text file and outputting it. I was able to write the same program fine in Java.
C++ :: Running A SLR Parser Program?
Apr 27, 2012I need to run a program that makes a SLR Parser Table.
Here is the code :
Code to find first and follow:
saved as SLR.h
#include<stdio.h>
#include<ctype.h>
#include<conio.h>
#include<stdlib.h>
#include<string.h>
#include<iostream.h>
#define epsilon '^'
since I didn't know how to type epsilon symbol temporarily I am using ^
char prod[20][20],T[20],NT[20],c[10][10],foll[10][10],fir[10][10];
int tt,tnt,tp,a;
int follow[20][20],first[20][20];
void first_of(char);
int count(int j);
void rhs(int j);
[code]....
C++ :: Parser Does Not Name A Type Error
Oct 22, 2014I am trying to write a program that reads in an XML file, parses it and prints out information about each tag. I am getting the following errors when trying to build the program:
Parser.cpp:24:1: error: 'Parser' does not name a type
Parser::getXMLData() {
^
Parser.cpp:120:1: error: 'Parser' does not name a type
Parser:rocessXMLData(
[Code] ....
Here is my code for the 5 files.
[ATTACH]main.cpp
[/ATTACH][ATTACH]Parser.h
[/ATTACH][ATTACH]Parser.cpp
[/ATTACH][ATTACH]Element.h
[/ATTACH][ATTACH]Element.cpp[/ATTACH]
C :: Text Parser - String Separation
Jan 4, 2015I would like to make a sort of text parser, in which one enters a string, and it is broken by the whitespaces into chunks, and those chunks compared to different "dictionaries" where the words are assigned a value. For example if the operator enters "take lamp" it would separate "take" and "lamp" and then produce preassigned values for each of these words.
View 3 Replies View RelatedC :: Simple Parser / How To Deal With Slashes
Feb 13, 2013I've knocked up a rough C parser for the purpose of colourizing code into XHTML/CSS, which makes me feel fancy. However, it doesn't quite handle comments properly. I can't quite work out how to deal with the slashes. Plus I'm sure there are other places that it slips up that don't feature in my simple tests, so here you go:-
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define FLAG_OUTPUT1
#define FLAG_EVEN2
#define NUMKEYWORDS32
}
[code]....
C++ :: Getting Segmentation Fault In Parser Code
Dec 23, 2014For some reason when i put cout<<endl i'm getting segmentation faults in my Parser code. It's really weird some inputs of strings using cout is already faulting. However sometimes printf doesn't fault, but sometimes it will, it seems really unstable.
The court can basically be anywhere in the Parse(string) function, i have a cout at line 254 which faults.
Here is the code:
#include "Parser.h"
#include <stdio.h>
#include <iostream>
using namespace std;
Parser::Parser() {
[Code] ....
C++ :: CSV Parser - Infile Using Variable Filename?
Jan 18, 2013So. I have a CSV Parser that I built. It works very well. The way it currently works is that I have the parser in a header file "CSV_Parser". So my .cpp code would look like this:
#include <iostream>
#include <eigen3/Eigen/Dense>
#include "CSV_Parser.h"
using namespace std;
using Eigen;
[Code] ....
This all works great. I am running Eclipse in Linux (Xubuntu to be precise). In the header file the .csv is opened as follows:
ifstream infile;
infile.open("/home/karrotman/Desktop/Matrix.csv");
What I would like is for the user to be able to change the file that the parser is opening through the main .cpp file. In other words, is there a way to create some variable, say "FileName" and do the following:
CSV firstMat;
string MatrixA = "/home/karrotman/Desktop/Matrix1.csv";
firstMat.extract(MatrixA);
CSV secondMat;
string MatrixB = "/home/karrotman/Desktop/Matrix2.csv";
secondMat.extract(MatrixB);
And then the .h would now say:
void extract(string FileName)
...
ifstream infile;
infile.open(FileName);
Obviously this does not work. Ultimately the goal is for me to open 4 .csvs at one time so I can do numerical operations on them.
C/C++ :: How To Do Error Handling In Predictive Parser
May 9, 2014#include<iostream>
using namespace std;
void E();
void T();
void F();
void match(char m);
[Code] ....
I have written this code for predictive parser. It is working for valid input but it is not working for invalid input when i give invalid input it says its valid. How to do error handling in predictive parser.
C++ :: Libjson Non-recursive Parser Function
Oct 8, 2013how to write a non-recursive JSON parser function using libjson in C++. libjson is quite useful librray. It's source code of libjson comes with an example C++ parser but it uses recursion to parse JSON arrays and child nodes. I am looking for parser function based on libjson that does not use recursion to parse JSON arrays and child nodes.
View 1 Replies View RelatedC++ :: SIP Parser And Header File Including (using Sofia-sip)
Nov 6, 2012I am currently developing a small quick'n dirty SIP (Session Initiation Protocol) parser. Its task is to read a file (or command-line argument) with a SIP requst and parse it using the sofia-sip library. It should exit either with "1" on parsing failure or "0" on parsing success.
I have taken the code snipplet from here: [URL] .... resulting in this source code:
Code:
#include <iostream>
#include <stdio.h>
#include <sofia-sip/msg.h>
#include <sofia-sip/msg_parser.h>
#include <sofia-sip/msg_mclass.h>
int main() {
char *msg_data = "...";
[Code] ....
When I try to compile the code using
Code:
g++ -o parser -I/usr/include/sofia-sip-1.12 parser.cpp
I get the following failure:
Code:
parser.cpp:10:45: error: "sip_default_mclass" was not declared in this scope ....
Visual C++ :: Writing A Lexical Analyzer / Parser
Oct 6, 2012I'm trying to learn more about how Lexical Analyzers/Parsers work. I haven't coded any classes yet, because i'm not really sure how the entire process from a Lexer to working code goes.
My goal is to write a simple made up programming language and translate that to another language, like Javascript. The first thing i have to do is give the code to a Lexical Analyzer.
The lexer will split the source into tokens and assign a label to it. So suppose i have the following code:
Code:
def myVar = 10;
The lexer will split that into token like this:
Code:
def -> keyword
myVar -> Identifier
= -> Operator
10 -> Number
That's basically as far as i understand what a lexer does. How can i translate the tokens to a language like Javascript? From what i understand i need to write a Parser class. But i couldn't find any info on what that class exactly does. So what is exactly the next step i have to take?
C++ :: Evaluating Arithmetic Expressions Using Recursive Descent Parser?
Feb 25, 2013I have the following code to calculate arithmetic expressions :
#include <iostream>
using namespace std;
using namespace std;
const char * expressionToParse = "6.5-2.5*10/5+2*5";
char peek(){
return *expressionToParse;
[code]....
The problem is that it does not work properly with decimal numbers for example it evaluates 6-2*10/5+2*5 = 12 which is correct but for 6.5-2.5*10/5+2*5 it returns 6 instead of 11.5 .
C++ :: Program That Handles Configuration Files - Config Parser?
Apr 9, 2013I wrote a small program that handles configuration files. I was wondering if this code is considered "good?" I am also wondering if there are ways to optimize it.
class configFile {
std::vector<std::string> variables;
std::vector<std::string> values;
public:
/* declare the constructor function */
configFile(std::string loc) {
[Code] ....
C :: Writing A Simple File / Text Parser To Read A Config File
Feb 6, 2014I am writing a simple file/text parser to read a config file for some code I am working on. It's dead simple and not particularly smart but it should get the job done. The code reads a config file:
Code:
readlength=2500000
start=0
finish=25000000
cutoff=20000
samplingfreq=250000
poles=10
filterpadding=500
}
[code]....
Here is where it gets wierd. You'll notice that there is an unused variable (filepath) in the config struct. This variable is not referenced or used anywhere in the code, ever. Yet if I comment out the declaration of char filepath[1024], the code segfaults partway through the read_config() function.
My best guess is that there is a buffer overflow elsewhere and it just so happens that the memory allocated for filepath happened to be there to catch it up until now, but I can't work out where it might be happening. With the declaration commented out, the read_config() function gets as far as reading the "padding" variable before it crashes. Yet when the declaration is there, then all the variabled are read correctly and everything seems to work.
C++ :: Expression Must Have Constant Value?
Oct 23, 2013line 27 and line 88 Im having a hard time figuring it out what the error is.
#include<iostream>
#include <cmath>
#include<algorithm>
[Code]....
C++ :: ATM - Expected Primary Expression Before Else
Mar 29, 2014I keep getting an error here and cant quite figure out why,
Code:
else if (mainMenu == 3){
cout << "Please make a selection" << endl
<< " 1) Withdraw from account" << endl
<< " 3) Back to main menu" << endl;
cin >> withdrawMenu;
if (withdrawMenu == 1){
[Code] ....
C++ :: Expression Must Have A Class Type?
Apr 3, 2014I am making a program that allows you to add two big numbers that are larger then what int can handle together. I think I have done everything to accomplish this but when I try to instantiate the program I get a error Expression must have a class type.
Here is my main file that is supposed to instantiate the program.
Code: #include "stdafx.h"
#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
#include <conio.h>
#include "LargeIntegers.h"
using namespace std;
[code]....
C :: Expected Expression Before Token
Jun 18, 2014I wrote a program, that generates 20 random integers, and stores them in an array. Then I decided, to build more functions to it, i.e why not have it to display the lowest integer of an array. I created my function,
Code:
int minValue( int field[ ] )
and got my code in side, which (technically) works. In my main() function I'm calling
Code:
printf( "The smallest value of an array is: %d
", minValue( field[] ) );
and I'm getting an error trying to compile it.
Code:
randomArray.c:62:74: error: expected expression before ']' token
printf( "The smallest value of an array is: %d
", minValue( field[] ) );
C :: Building NFA From Regular Expression
Oct 23, 2013I am trying to create a NFA from a regular expression. I have a grasp on reading in the regular expression and being able to make a stack from it. The part I am struggling on is mapping the characters in the regular expression to an integer indicating the variables order in the expression. I am just not sure how to go about this.
My code so far...
Code:
#include<stdio.h>
#include<stdlib.h>
#include "stack.h"
int main(void)
{
char expression[80];//array to store regular expression
[Code] .....
C :: Syntax Error In Expression Near If
Feb 3, 2013I am using code::blocks for c programming and when i take debugger in below code it show ..
a syntax error in expression near "if"..
I am just checking debugger ...
Code:
#include <stdio.h>
#include <string.h>
int main()
{
char s1[100];
[Code] ....
C :: Calculation Of A Bitwise Expression
Mar 6, 2015I would like to ask about how we calculates the following bitwise expression.
Code:
unsigned char ch[2] = {0x49,0x49};
ch[0] | ch[1] << 8; I'm thinking ch[1] << 8 as 0x00 ...
So, I think that the above expression converts to 0x49 | 0x00 ... and the complete expression should be 0x49 for me.
But, the compiler gives me the result of 0x4949 as two bytes.How does the compiler calculate this expression as two bytes?show me the steps included in the calculation of this expression?
C++ :: Expected Primary Expression Before INT
May 26, 2014This is what i have example code in c++:
#include <iostream>
class Foo{
public:
void bar(){
std::cout << "Hello" << std::endl;
[Code] ....
After compiling it is giving error as :
foo.cpp: In function ‘int Foo_max(Foo*)’:
foo.cpp:26:37: error: expected primary-expression before ‘int’
foo.cpp:26:46: error: expected primary-expression before ‘int’
C++ :: Expression - Value Returning Function
Dec 17, 2014How is the definition of the term "expression" affected by value returning functions, and why?
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