C++ :: Dynamic Function Execution Based On String Input
Jun 27, 2013
I've got some functions and macros that I want to execute based on a string input that matches the function's name. I came across as this being a possible solution that I'd like to pursue IF it is possible to do. To clarify, I want to be able to look at a string and if the string matches the name of a defined function or macro then it will execute. Is there an effective way to do this (or is it even possible)?
It has to be pretty robust and dynamic given the project's purpose. Basically there's an input file that is being parsed and functions should execute if called upon in the file. I can't simply match strings to their corresponding functions in decision statements, as this isn't robust and isn't scalable.
#include<iostream> #include<ctime> #include<boost/progress.hpp> using namespace std; class parent { public: virtual void dynamic_display(){
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I am getting the following as output
Calculating....Static Function is called1times The number of processor clicks is0time is0 Calculating....Dynamic function is called1times The number of processor clicks is0time is0 Static Function is called2times Dynamic function is called2times Static Function is called3times Dynamic function is called3times
I am actually trying to calculate the time to execute a statically binding method and a dynamically binded one.consider only the first four lines in my output. Why am i not getting the actual result.
I Need to write a function using C wherein I should do the following:
(i) The function will receive a string in a character pointer
(ii) This string will adhere to the following structure: "Kentucky+New York+Arizona+Nevada" The number of states can differ from 4 to 50 The delimiter between States can differ from '+' to ',', hence I would like to pass the delimiter to the function.
(iii) This string should then be sorted alphabetically from left to right. The above example would then become: "Arizona+Kentucky+Nevada+New York"
(iv) This string needs to be returned from the function using a character pointer.
I have a class called Book and I am trying to create a dynamic pointer based array of the class. When I try to run the program I keep getting the error: pointer being freed was not allocated at the line of code that says "delete [] A;". I am using Xcode to run the program.
Book *changeArraySize(Book *A, int &size, double factor) { int i; int newsize = size*factor; Book *A2 = new Book[newsize];
I want to write a function and be able to call it during execution (say during a while(1) loop). Is this possible without having to parse an input string to extract the function and parameters I need or is that the only way?
class MyClass{};namespace BI{ class BusinessInterop { public: static MyClass* func( { printf("BusinessInterop");return new MyClass();}
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I would like to know how to prevent the program print out "Business", I'd like it to call the base class's static function. I have tried to changed MyClass* into void* but it still prints Business :grumpy:.
My challenge is to output "BusinessInterop" without any changes made to the polymorphic structure as designed.
I am getting an anomalous output. Before all the iterations of for loop could finish, the program enters into the invoke_thread_S() and I can see the remaining iterations of for loop happening after thread S is finished.
What could be the problem here. Can I put a 'sleep' before I enter into invoke_thread_S() function, I tried it with a very small amount (in nano seconds), but that did not solve the problem.
i have to write a function to modify the input string by substituting each alphabetical character. for example, 'Programming' to 'Rtqitcookpi' (mod_int = 2).
I am doing an assignment that is to calculate the federal tax based on the users input. I am not entirely sure what it is doing, but it is definitely not what I want it to do. I commented out the loops because they seemed to have caused a problem, but there is still problems that are making the program do something else. Here is my code:
#include<iostream> #include<string> using namespace std; double getData(); double taxAmount();
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Functions just seem like they are not my thing. It never gets to the second function to do the calculations and then return to main to display the results.
I tried changing the code to a switch(status) with a default: at the end that looped the "please try again" but for some reason, that was a fail, it created an endless loop.
My assignment is to pixelate an image based on users input. I have a structure that stores the image, and in this structure I'm storing the height and width and a dynamic array of RGBA struct.
This is my function. my main issue (that I've found) is offsetting and figuring out a way to handle the "edge" if the dimensions don't add up to the set pixelation size.
Player is given choice of x number of Races This choice changes the player's base stats. Then player is given a choice of x number of Classes (archer, warrior, etc.) This choice determines how the player's stats will change upon leveling up.
I just don't understand how you would have it count how many negatives and positives there are based on the user's input? Here's the problem and the code it provides:
Modify the program so that is displays the average of the positive and negative numbers. (Hint: be careful not to count the number 0 as a negative number.)
Code:
#include <stdio.h> #define MAXNUMS 5 int main() { int i; float number; float postotal = 0.0f; float negtotal = 0.0f;
I have been tasked with making a diamond out of asterisks based on a given odd integer input. For some reason the bottom half of my diamond will not print. I'm not sure as to why.
how to stop outputting data based on a user input. The text file is as follows:
1. a 2. b 3. c
and the code I'm using is as follows:
int main (){ string line; int search; cout << "Enter a number from 1-3" << endl; cin >> search; search++; ifstream myfile ("example.txt");
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What I want to do is to just output number 1 (the whole line) if the user enters number 1. However, I get an error on the second condition w/c is the "&& line!= search"
I'm trying to increment the values in a vector, not the vector size, based on variable input. Basically I have a vector of size 10, and all of its values are initialized at zero. The program counts the frequency of numbers 0-9 in a four digit user input. This is what I have (I want it to work so badly but the compiler says that I'm using a pointer to a function used in arithmetic):
for (int i=0; i < num_slots; ++i) { ++guess_frequency[guess[i]]; }
I just want to know if you can increment values within a vector:
I'm trying to create a function where it allows the user to type in multiple amounts of integers, so if the user wanted to have 3 different storages that hold different integers, the input would look something like this:
5 97 12 31 2 1 //let's say this is held in variable "a" 1 3 284 3 8 // "b" 2 3 482 3 4 // "c" 2 3 4 2 3 // "d" 99 0 2 3 42 // "e"
Since we don't know what number the user will input every time, I'm not sure how to create a dynamically allocated array that will create an x amount of arrays every time.. I want to be able to access each index of a, b, c, d, e or however many arrays there are.
So far, this is what I have, but I'm having trouble creating the arrays since it's unpredictable. I'm purposely not using vectors because I don't really get how pointers work so I'm trying to play around with it.
int* x; int length, numbers; cin >> length; x = new int[length] for (int i=0;i<length;i++) { cin >> numbers; //this doesn't work because it only grabs the first line for some reason x[i] = numbers }
I am trying to create a program that will calculate pi based on a user input for accuracy. If the user input .3 then when the leibniz infinite sum value at a particular i becomes less then the input of .3 then the loop will exit.
I have looked at a number of examples on the internet but I feel lost. I have put together working code that will infinitely output sums but I need the loop to stop when the sum value is less then the accuracy value.
My question is what is wrong with my while loop, why will it only give me infinite summations? How do I make it so that the loop will exit when my accuracy input is greater then the sum?
int main () { double accuracy; cout<<"Give an accurate number." << flush;//looks nice cin>>accuracy; int d;//initialize denominator double pi = 0.0; while(accuracy < d){
i want to display all the contents of a file excluding one based on user input say i have 4 records in the file numbered 1 to 4....the user chooses 2 to exclude it outputs records 1,3,4,4 when it should be records 1,3,4 what am i doing wrong here is the code.its basically displaying the last record in the file twice
Here is the assignment... Write a program to generate a report based on input received from a text file. Suppose the input text file student_status.txt contains the student’s name (lastName, firstName middleName), id, number of credits earned as follows :
Doe, John K. 3460 25 Andrews, Susan S. 3987 72 Monroe, Marylin 2298 87 Gaston, Arthur C. 2894 110
Generate the output in the following format :
John K. Doe 3460 25 Freshman Susan S. Andrews 3987 40 Sophomore Marylin Monroe 2298 87 Junior Arthur C. Gaston 2894 110 Senior
The program must be written to use the enum class_level :
The function deriveClassLevel should derive the class_level of the student based on the number of credits earned.
The first namespace globalType tys should derive the class level based on a two year school policy. And the second namespace globalType fys should derive the class level based on a four year school policy.
Four Year School Policy: Freshman 0-29 creditsSophomore 30-59 credits Junior 60-89 creditsSenior 90 or more credits
Two Year School Policy: Freshman 0-29 creditsSophomore 30 or more credits
My main question is did I use the namespaces and enum correctly? And my second question is whats the best way to input the data from the text file? This is really where I get stuck.
Write a program to generate a report based on input received from a text file. Suppose the input text file student_status.txt contains the student’s name (lastName, firstName middleName), id, number of credits earned as follows :
Doe, John K. 3460 25 Andrews, Susan S. 3987 72 Monroe, Marylin 2298 87 Gaston, Arthur C. 2894 110
Generate the output in the following format :
John K. Doe 3460 25 Freshman Susan S. Andrews 3987 40 Sophomore Marylin Monroe 2298 87 Junior Arthur C. Gaston 2894 110 Senior
The program must be written to use the enum class_level :
The function deriveClassLevel should derive the class_level of the student based on the number of credits earned.
The first namespace globalType tys should derive the class level based on a two year school policy. The second namespace globalType fys should derive the class level based on a four year school policy.
So I basically did it in parts and got everything working and then had to make the namespace so I had this:
with this i keep getting an error saying tys::deriveClassLevel: must return a value and tys::fys::deriveClassLevel: must return a value. I have been messing around with this part and struggling I thought I used the namespace to run the if statements with the criteria for the years of school. Basically I have been stuck for awhile and trying to change things around but I cant seem to get it to work.
I need to create a program that prints a certain number of asterisks based on user input. The user inputs 5 and I want my program to output "*****". How would I do this in C? I've tried printf("%#**", myvariable) but this does not work it only prints "*".
I want to have input data stored in a database. All information entered is to be stored under a single block. That way whenever I want to recover that information all I have to do is point to that block. Think of it like this. I want a large square block that can hold certain information. Inside of that large block are a finite amount of smaller blocks in which the user entered information about a single subject. Lets say block 1 has a name, address, and phone number. The second block will have the same TYPE of information, but different values as entered by the user. I.E:
BLOCK 1: Name 1, Address 1, Phone 1 BLOCK 2: Name 2, Address 2, Phone 2 etc.
The large block contains all of the smaller blocks, we will name the large block "Address Book" ... How would I implement that? Of course it would be just a simple console program that would erase all information when the program shut down, but I've been trying to figure out how to do it, but just can't seem to grasp a good notion of how to do it. What would be the best way to do that? Structures? How would I make it dynamic so that I wouldn't have to define every block, so that it would be added on the fly when someone inputs new information.
I'm now working on a class to handle matrices and matrix operations. I dynamically allocate a two dimensional array with its size as an input. My problem is that i need to resize the matrix structure (to fit to the size of a product of two matrices or to adjust the size after deleting a row or column for example). I make the resizing by deleting the allocated 2d array after saving its first element address to another pointer to pointer, after saving the useful data in an other array, then i use new[] operator to create a new 2d array using the same address of the old deleted array.
void My_matrix ::delete_row(int a) { int i,j; int buffer_row_index = -1; //note that our work is zero based, as we acess the private member of an object of the same class we are working on and we access to the array as it is (zero based) so if this variable is -1, it will be 0 when it enters for the first time and saves the data in the right position. My_matrix buffer(number_of_rows-1,number_of_columns);
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I do this in a way that i think is unsafe. This code is sometimes unstable and gives an unhandled exception whose reason is unknown. I need to know whether this way is good enough or if there any other better ways.
In my homework, x is unknown. but don't worry, I wont ask for the full code. I just need the part where you change the int into a string/array of char.
