I have to write a loop assigning a variable x to all positions of a string variable and I'm stuck. I don't have extensive experience with arrays and I'm also a bit confused about C-String. The problem is below.
"Given the following declaration and initialization of the string variable, write a loop to assign 'X' to all positions of this string variable, keeping the length the same.
char our_string[15] = "Hi there!";
(Please note this is a 'C-string', not C++ standard string.)"
My assignment is to write a binary calculator that works with floating point for simple math (+,-,x,/). How to do this. the binary numbers need to be from the user.
I've come to a point where I want to manipulate an image file at run time or with pre-determine sizes and have to be applied when the windows is moved or through in program options.
I know I can do the applying part. However I am a little unsure of how to tackle the image manipulation. I want to make it so that it is not os dependant. So I know I can not rely on any os functions. The only other thought that came to mind was to deal with the video card itself.
So the main question after all of that is said and done. How is c++ able to interact with the video card directly for images? Or if there are existing function I can use. How do they do that? If I can use existing function I would like to be able to manipulate it myself.
How I can manipulate certain strings. This program here is supposed to randomly scramble any word/sentence input. However, I notice that even the empty spaces get moved; is there any way to stop that from happening? I would want the empty spaces to stay in their input positions.
I need a translate (in both directions) all primitive types, into char[] (will be stored in string)
I understand how to manipulate integral types with bits and I cant just cut them down and shift them, but float and double don't work with this manipulation. So, how I can create a perfect bit copy of float and double?
int i = 0xFCED03A4; //Random number char c[4]; c[0] = ((i >> 3) & 0xFF); c[1] = ((i >> 2) & 0xFF); c[2] = ((i >> 1) & 0xFF); c[1] = (i & 0xFF);
[Code]...
This is basic stuff but I need an equivalent for float and double types, and it needs to be a perfect BIT copy, not value copy.
here i have an assignment, creating a longInt class and using it to calculate large numbers, i dont have a clue how to manipulate a whole array as a single ineteger.
I'm trying to write a program that manipulates a doubly linked list. My professor wants it to have two structs, one called Node (containing the data, and pointers to the next and previous nodes) and one called DLList, which contains the nodes for the head and tail (which is then passed to all of my functions).
I'm a little confused how to access the head and tail, for instance, if I want to initially set them to null in the main function (he emphasized the need for this), or to use them in my functions. I've tried a lot of variations to call the head and tail, but I keep getting told that head and tail are undeclared in the function.
How might I access my head and tail, for instance in a main function, when they're defined like this? (I took out all of the logic in my functions for clarity)
Essentially what I need to do is take a text file, ("input.txt"):
4 4 1 0 0 1 1 1 1 1 0 0 1 0 0 0 1 0
And take the first two values on line 1 (4, 4) and use them as length and width. Number of rows: 4 Number of columns: 4
Then I need to print out the matrix and further manipulate it. I need to find the sum of the 1's per column and then take that number and replace each 1 with the 1's in each column.
The part that's mostly troubling me is that my instructor will be giving me the input file with random values, so I don't know what the matrix dimensions will be.
I can read the 2D array but can't seem to use it after. I need to find a way to skip the first line, and then read in the matrix and be able to use it mathematically to add up each column.
I made a program that can use a function to manipulate data from a list class. The program is very basic and I think the error makers may be obvious to some of you. I just wanted to find it without having to scrap my program. It doesn't generate a compile error but it announces a memory error while it is running. I use visual studio 2012, the program is an exercise from a c++ book.
list.h #ifndef LIST_H_ #define LIST_H_ typedef double Item; const int MAX = 10; class List
Create an application to manipulate an array of student record objects. A student record will consist of a name (first, middle, and last), an ID number (9 numeric digits, cannot be more or less), an address (street, city, state, and 5 digit Zip code), and a phone number (3 digit area code and 7 digit number). The application will support an array of students. The user will be allowed to enter records from the keyboard, sort records by either name (last, first, middle) or by ID, save the records to a disk file (name supplied by user), and read the records from a disk file (name again supplied by user).
Create a fixed length string that must check that the length of the string is the required length. The fixed length class should be done as a template with the number of characters as the template argument. From this fixed length string, derive a class to hold digits of a fixed length.
Create component classes as necessary to use together to implement the student record class.
Use either the array template created in an earlier lab to handle the array or you may use the vector class from the STL to handle the array of student record objects.
The maximum number of students will be 25 (it may be less).
As written in the title, I want to be able to extract a variable value from a string containing the variable's name. I know one can use associative containers such as maps but is there another more direct way?
E.g.:
int variable = 5; string str = "variable";
// how do I get the value of 5 out of the string containing the variable name?
If I am correct, this is called 'Reflection', correct me if I'm wrong.
I know C++ has no inbuilt 'Reflection' class or anything like that so I was wondering if there is a workaround for this kind of thing or is there a library out there which can do this? (that's if I have the name right).
I have found a library called Boost Reflection which sounds like it could do this but I just wanted to make sure that reflection is actually what I am talking about and whether C++ can do what I'm trying to do? I'm not sure how.
Im trying to write a program that reads in strings and decides if the 1st one is repeated. I cant figure out how to store the first string into a variable, and compare that variable to the rest of the inputted strings.
Code:
#include <strings.h> #include <stdio.h> int main () { //Declared variables int i; }
I have defined a class in a header file; just the class, no templates involved. I have a program where I'm reading in data in string format. Each string consists of a word, a delimiter, and a variable name. Example:
cajun/mustard
I want to take that string and make it the variable name of that class type. It would be implemented along the lines of:
Code: string str; //read/process string here, get: str = "mustard"; createName(str); //pass string to creator function When the function is called, I should get the variable: Class mustard;
Thing is, I'm not supposed to know beforehand what the variable names are, only that I create them as they are read in. It could be mustard, it could be Maynard_James_Keenan, it could even be bazinga.
My problem is, what do I do for createName()? I've looked into the concepts of pairing, Factory implementation, and maps, but I don't think they answer my question.
(P.S. if I run into the same variable name being read in twice, what steps can I take to make sure that a duplicate variable isn't created? Do I need to add in code, or does the compiler know to watch for multiple variables of the same name?)
I am trying to read a tab delimited file containing 8 columns and store each element of the column as an 1-dimensional array. Though the program prints the strings correctly as in the commented printf but it doesn't give me first_col[0] value and so on. My code is as follows:
Code:
#include<stdio.h> #include<stdlib.h> #include<string.h> int main() { FILE *int_file1; int BUF = 1024;
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The inputfile test.txt has the following elements:
I need to create dynamic string by given format(%d,%s,%f,%lf,%c) using variable number of arguments in function. This code gives me an error(main.exe has stopped working):