I'm currently finishing up an assignment that was half written by my professor. Below in the testGrades section of code there are two errors both are the same message.
Error: no matching function for call to Grades:: Grades(const char [15])
Test Grades
//Purpose: Test program for the class Grades
// Create stu1 Grades object
// Add 5 grades to stu1 - only 3 can be stored in stu1 - other 2 discarded
// Create stu2 Grades object
// Add only 2 grades
I have a file which contains a year and the name of an associated file to be read. I need to extract the data in the txt file and perform some calculations.
（ year data file） 2004 2004data.txt 2005 2005data.txt 2006 2006data.txt
Here is what I do. I first declare "char yeardata" and then pass "2004data.txt" to it. Then I call yeardata in ifstream to extract the data inside the file "2004data.txt". The problem is that char yeardata is not constant so I cannot pass the file to it. It doesn't work if I change "char yeardata" to "const char yeardata".
Code: int oldnewcomp_temp(char* lcfile) { using namespace std;
I want to use a const char* as a buffer. I am reading values from a file and adding them to a buffer. How to extract the values is simple enough. I am reading through a filestream, reading each character into a char pointer and progressing that char pointer every time. I have another char pointer marking the start positon
eg.
char *mychar = new char; char *char1 = new char; char *char2 = new char; const char *constchar ; char2 = char1; while(filestream.read(mychar,1) { *char1 = *mychar; ++char1; }
Then I get this problem: constchar = mychar; // const char* = char*.
Constchar does not catch all the data in other words. At some stage some data is lost due to zeros in the data.. How can I put values into a const char and get around this problem? The const char* will //only record everything up until the first zero.
I have data that is coming into my buffer via popen (process data, not a file). Every seven records is a new set [0-6]. I am trying to 'print out the array line/element value' and 'change the value of element [2] to 0', but my loop appears to be looping through every character and not just every line?
What is the programmers responsibility with respect to const char * returned by various functions, like the C++ string class c_str() function which returns a const char * to an c style string array? In VC++ I cannot delete a const char * which holds a string literal. Take the following code for example:
Code: void func() //a useless function with illustrative code { string s1("abcd"); string s2("efgh"); const char * cc1 = s1.c_str(); //c_str() returns a const char * c style string pointer s2.c_str(); //this returns a const char *, which must be allocated on the heap right? delete cc1; //produces run time error in Release mode in VC++ }
The problem with the above code snip is that space is allocated on the heap (or so I believe) for the const char *'s returned by the 2 calls to c_str(). The delete attempt fails and there is no opportunity to delete the space allocated by const char * because its not assigned to anything (however I see c_str() used this way extensively)
So, if I cannot delete a const char *, how does the memory get recovered? Perhaps the string objects s1 and s2 themselves have pointers to the items on the heap made by c_str() calls and they get deleted by the destructors of s1 and s2 when the function ends?
I have data that is coming into my buffer via popen (process data, not a file). Every seven records is a new set [0-6]. I am trying to 'print out the array line/element value' and 'change the value of element [2] to 0', but my loop appears to be looping through every character and not just every line?
199729173 2014-11-16 10:09:34 Found String! 198397652 2014-11-14 15:10:10 Found String! 198397685 2014-11-14 15:10:13 Found String! 198398295 2014-11-14 15:11:14 Found String!
I have a class that defines a window (a popup dialog of sorts), and I want the name of that window to be constant. The only problem is that the name of the popup needs to match the title of the parent window, and I get the name of the parent in the constructor. So how do I go about defining this member variable to be constant and initializing it with a value in the constructor?
I want to do something like this, but I know this isn't allowed:
/* class.h */ class foo { public: foo(*parentWindowPtr);
[Code] .....
I should mention that yes the name of the parent window is const char *, and I would like to keep it this way.
I am a newbie to C++ and VS ++. I have created a windows form application by dragging and dropping button, label..etc. i wish label text to be appeared as return value from a function. The function returns ' const char* '.how this returned string pointer can be used to display label text.?
Code: g++ --g -c ErrorH.cpp -o ErrorH.o ErrorH.cpp: In static member function "static ErrorH& ErrorH::Instance()": ErrorH.cpp:9: error: invalid initialization of non-const reference of type "ErrorH&" from a temporary of type "ErrorH" make: *** [ErrorH.o] Error 1
This code works on Windows, how can I get it to work on Linux?
The problem with that is that string.data isn't considered const during the initialization of the String struct so the compiler throws an error. It doesn't feel very elegant to do it like this either way.
Is there an elegant solution to this problem? I would like to avoid making a copy of the string literal.
Are there other ways of calling a const/non-const override? I want to defined some functions in terms of others, particularly accessors which might or might not require constness- in order to not copy & paste code. This is my current solution:
difference between const and static const, more effectively. I know the basic concept of const and static but I need clear explanation of declaring "const" and "static const"
Is there any way to cast a non-const variable to const one?
I want to read variable n from file and then use it to declare array "int arr[n]", but because n is non-const, the compiler doesn't allow me to do that.
I've just recently started to learn C++, and I'm encountering some errors I can't seem to figure out.
InventoryItem.h:
Code: #pragma once class InventoryItem { public: InventoryItem(string name, int amount); ~InventoryItem(void); string getName(void); int getAmount(void);
I have the codes for such a problem where, to create a program that counts how many times the second string appears on the first string. Yes it counts if you put 1 letter only, but if you put 2, it is an error. As an example. If the first string is Harry Partear, and the second string is ar, it must count as 3. Here's the code:
Code:
#include <iostream> #include <conio.h> using namespace std; int main ()
I'm trying to "tokenize" a string using std::string functions, but I stored the text in a char array. When I try to convert it to a string, the string has the first character right but the rest is garbage.
// Get value from ListBox. char selectedValue[256]; memset(selectedValue, NULL, 256); SendMessage(GetDlgItem(hWnd, IDC_LB_CURRENTSCRIPT), LB_GETTEXT, selectedIndex, (LPARAM)selectedValue); // Convert to string. string val(selectedValue);
I am tying to convert an int to a char. Below is an example of the code that I have but I am getting an error('=':left operand must be l-value). I am not seeing a problem with the code.
int num = 5; char temp[2]; char final[2]; itoa(num, temp, 10); m_pRes->final = temp;
I'm writing a small piece of code that increments through a string of numbers. For every 5 numbers a product is produced. However i'm having an issue understanding an error that keeps occurring.
if you look at the code i've got a string with 5 numbers 1-5 for testing. As the loop increments through the string it takes the first 5 characters and converts them to integers and then a product is returned. The issue is that instead of storing the single letter at position J its storing some combination from the string and as a result gives me a huge product. I tried debugging. I checked what the string[j] value was with a simple cout << and it returned the right number. I even returned the char value before it was converted into an integer and it was the right number.
Well I tried to assign a new char value from a struct to another char variable but I got the "Cannot convert 'int' to 'char'" error when compiling. I've tried several alternations but I still can't get away with this error.
Here's a section of the code:
javascript:tx('code') for(int i = 0 ; i < 10 ; i++){ pts[i].dist = sqrt((pts[i].x*pts[i].x)+(pts[i].y*pts[i].y)); }
Ok so I am back in school and it has been to long since I have used c++ I can not find or figure out how to convert a char array into a int array so i can add numbers really large numbers. the string is being passed into the function as a const char*...
