How do I have the display function display the info within its function body? How to call it? The function is filled with the data I want outputted yet how do I call it and display the contents of the function.
int main()
{
InputValue();
displayinfo();
}
void displayinfo(int d, array<char, 7> b)
{
for (int k = 0; k < d; k++)
{
cout << "Semester: " << b[k] << endl;
}
}
I am trying to compile the below code, but I am getting the error:
wrong number of template arguments
template<int start, int end, int step>
struct range{};
template<int start, int end>
struct range<start, end, 1>{};
template<int end>
struct range<0, end, 1>{};
int main() {
auto r1 = range<0, 5, 2>{};
auto r2 = range<5, 15>{}; //error: wrong number of template arguments
auto r3 = range<10>{}; //error: wrong number of template arguments
}
How can I create partial template class object?
I've got the following piece of code:
std::string header(4, char{});
assert(header.length() == 4);
I'm wondering whether my assertion shall hold valid for the most popular compilers (VisualC++, GCC, clang). If not, for which versions does it hold valid, or from which version onward does it hold valid.
I'm assuming it must hold valid, and my assumption is from this reference:
My question also arises because this is inconsistent with the traditional behavior of strlen, and char_traits::length()
Hello everyone Im having a very hard problem doing what I need this code to do for my c++ assignment!
The desire I want my code to do is have the function InputValue() fill up the arrays I have made; Which it does perfectly! Then pass those arrays to a function called displayinfo() which will display the contents of the array when called in the main() function!
The problem I have ran into is when I try to call on displayinfo(sem1array) with the array I want to pass ultimately all of them, it comes up with a syntax error!
How should I pass the contents of the various arrays sem1array,sem1coursetypes, sem1coursetitles,... into the function that displays the contents and then how should I call on the function to display the contents within main() function?
And another huge question I have is; Is there another way of writing or declaring an array other than array (right open arrow)char,7(left open arrow) sem1array; like the way I have declared all the arrays in my code?
I have put stars on all the parts where i'm having the problem! I left the other code in so you see how the arrays are filled and what i'm working with.
#include<iostream>
#include<array>
#include<iomanip>
#include<string>
using namespace std;
void setCourseName(string);
void InputValue();
int main()
{
InputValue();
***displayinfo();***
}
void InputValue()
{
char semester;
string courseTitle;
string courseType;
int credits;
string lettergrade;
double gpa;
array<char, 7> sem1array;
array<string, 7> sem1coursetitles;
array<string, 7> sem1courseTypes;
array<int, 7> sem1credits;
array<string, 7> sem1lettergrades;
for (int counter = 0; counter < sem1array.size(); counter++)
{
bool valid1 = false;
bool validCredits = false;
bool valid3 = false;
bool valid4 = false;
while (valid1 == false)
{
cout << "Enter Semester Number" << endl;
cin >> semester;
if (semester == '1' || semester == '2')
{
cout << "valid input" << endl;
sem1array[counter] = semester;
valid1 = true;
}
else
{
cout << "Invalid Input! RE ENTER SEMESTER NUMBER EITHER 1 OR 2!" << endl;
}
}
cout << "Enter Course Title: " << endl;
cin.ignore();
getline(cin, courseTitle);
if(courseTitle.size() <= 25)
sem1coursetitles[counter] = courseTitle;
else
{
cout << "Course Name Cannot Be More Than 25 Characters; Course name limited to first 25 characters!" << endl;
courseTitle = courseTitle.substr(0, 25);
sem1coursetitles[counter] = courseTitle;
}
while (valid3 == false)
{
cout << "Enter Course Type: Regular, AP, or Honors" << endl;
getline(cin, courseType);
if (courseType == "Regular" || courseType == "AP" || courseType == "Honors")
{
sem1courseTypes[counter] = courseType;
valid3 = true;
}
else
{
cout << "Invalid Input! RE ENTER COURSE TYPE EXACTLY HOW IT APPEARS EITHER Regular, AP, or Honors!" << endl;
}
}
while(validCredits == false)
{
cout << "Enter Credits Earned For Course: **Can Either Be 1-4 Credits**" << endl;
cin >> credits;
if (credits == 1 || credits == 2 || credits == 3 || credits == 4)
{
sem1credits[counter] = credits;
validCredits = true;
}
else
{
cout << "Invalid Output! Must Enter Number 1-4 For Credits Earned!" << endl;
}
}
while (valid4 == false)
{
cout << "Enter Letter Grade; Capital Letter Followed By A Plus + or Minus - If There Is One!Example: A+, A-, A, B+..." << endl;
cin.ignore();
getline(cin, lettergrade);
if (lettergrade == "A+")
{
gpa = 4.0;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else if (lettergrade == "A")
{
gpa = 4.0;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else if (lettergrade == "A-")
{
gpa = 3.7;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else if (lettergrade == "B+")
{
gpa = 3.3;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else if (lettergrade == "B")
{
gpa = 3.0;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else if (lettergrade == "B-")
{
gpa = 2.7;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else if (lettergrade == "C+")
{
gpa = 2.3;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else if (lettergrade == "C")
{
gpa = 2.0;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else if (lettergrade == "C-")
{
gpa = 1.7;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else if (lettergrade == "D+")
{
gpa = 1.3;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else if (lettergrade == "D")
{
gpa = 1.0;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else if (lettergrade == "F")
{
gpa = 0.0;
sem1lettergrades[counter] = lettergrade;
valid4 = true;
}
else
{
cout << "Invalid Input! Please Re-Enter Letter Grade! Example: A+, A-, A, B+..." << endl;
}
}
}
***displayinfo(sem1array);***
}
***void displayinfo(char b[])***
{
for (int k = 0; k < ***sem1array.size()***; k++)
{
cout << "Semester: " << sem1array[k] << " " << "Course: " << sem1coursetitles[k] << endl;
}
When using the asynchronous tasks from the C++ REST SDK, is it possible to apply synchronization tools from the multithreading standard library? Example:
http_client client(U("whatever"));
http_request request;
int i = 0;
client.request(request).then([&i](http_response response) { i = 1;});
//here use variable i
The above code obviously introduces a race condition, which in principle could be cured by using a std::mutex or std::atomic. Is this possible, i.e. does the underlying asynchronous task implementation respect this mutex? And if it is possible, is it so in a platform-independent way?
I've got a little templating scenario I'm dealing with. Here's the setup for it.
class Base {
}
class Derived : Base {
};
And my use case:
void DoAThing(Base* t) {
DoAnotherThing(*t);
}
template<typename T>
void DoAnotherThing(T& t) {
}
So what I was hoping for was that I would be able to pass a Derived type into my "DoAThing", and then when I pass it through to DoAnotherThing, the template parameter would appear as Derived. I can see that the dereferenced type definitely is resolved by typeid as Derived, but the T type of DoAnotherThing always comes through as Base. Is there any way I can manipulate this so that DoAnotherThing resolves to the derived type that I send?
Edit: Thanks for the answers so far, but it's not quite solved for my use case yet. DoAnotherThing is to actually to create a container of the Derived class, and the problem is that the container type ends up as Container rather than Container. I want DoAThing to continue taking in the Base rather than be templates for the scenarios in which it is called.
This question already has an answer here:
If I have
int x = 25;
int& y = x;
I understand that x and y point to the same memory location. However, when I have:
int x = 25;
int&& y = x;
I get:
error: expected unqualified-id before '&&' token
What is the explanation in terms of lvalue and rvalue? I cannot wrap my head around the concept and how it is applied here.
Also, is it true that if you want to reference a number, you should only be able to do it using something like const int& z = 25 and never int& z = 25 because of the reason that you are referencing a number and numbers don't change?