I have a nested record structure in C++ that contains a FileHeader record, a RecordHeader record and a DataRecord record. The last item is an array of unknown size (at compile time). I have to open a file and read the array size and then create the array.
I have worked on this for some time and can't figure out how to make it work. I know the sample data I am using has 85 records. I insert 85 into the array size and it works fine. But how do I create a dynamic array or define a vector within a nested structure?
1. What is the best (easiest) method to accomplish this (array or vector)?
2. How would it be implemented/how do you add data to it?
PreviousLogRecord.FaultRecord.push_back(field1); // does not work
PreviousLogRecord.FaultRecord[recordNumber].field1 = somedata; // works with 85 in array size.
struct LogFileHeaderRecordType {
QString field1;
int field2;
I've been able to write the program completing all requirements except for one... creating a function that accepts a nested structure array. Here's the program:
I am not able to assign value into struct addrinfo variable through struct sort_result structure variable.
struct addrinfo { int ai_flags; /* Input flags. */ int ai_family; /* Protocol family for socket. */ int ai_socktype; /* Socket type. */ int ai_protocol; /* Protocol for socket. */
What happens is, after having called the collisionDestroy-function and the program tries to execute the nest loop in the outer for-loop, it all crashes with the text "Expression: vector iterator not decrementable", which I understand is because the iterator will have already become useless. The question is: know this, how do I fix it? I can't seem to get a hang of it.
Here's the collisionDestroy-function (the collisionReaction does nothing but sets a few local variables):
void Enemy::collisionDestroy(std::vector<Sprite*>& sprites) { for (std::vector<Sprite*>::iterator iter = sprites.begin(); iter != sprites.end(); iter++) { Enemy* tmp = dynamic_cast<Enemy*>(*iter); if (this == tmp && collisionType == 3 || collisionType == 1) { sprites.erase(iter); break; } } }
And came across the following error during link stage: "/usr/include/c++/4.6/bits/stl_vector.h:1080:4: error: no matching function for call to ‘std::vector<cv::Point_<int> >::_M_fill_initialize(std::vector<cv::Point_<int> >::size_type, int&)’ "
Example : Code: struct x { int v[4]; }; const x test = { 0, 1, 2, 3 };
Why can I do this? How does the compiler know to write to this in the proper way? I get that v would be contiguous. Does that have something to do with it?
I want to know this because if I happen to want to use a lot of insertions and deletions then it is more efficient to make use of Linked List instead of Dynamic Array.
While, if I happen to want to just access random parts of the Array, then Dynamic would be more efficient.
I want to make a 2D game using SDL engine and I need to check whether or not an object is colliding with a list of other objects. (because there would be more then one objects on the map.)
Since I would simply be accessing each object sequentially to check whether or not the object is colliding with another the object in question, and since any of those objects could "die" and be deleted at any time, it makes more sense to use Linked List then a Dynamic Array.
This creates quite a mess. It seems that somehow the "vector" declaration isn't working as the referenced web link seems to suggest that it should. I presume that, as usual, clearing one real error will eliminate the cascade of errors the first real error produces. Why won't VC++ accept the "vector" identifier?
The error messages that follow the build attempt are:
Friedman.cpp d:documents and settingsxxmy documentsvisual studio 2010projectsfriedmanfriedmanEinstein.h(22): warning C4996: 'fopen': This function or variable may be unsafe. Consider using fopen_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS.
I wrote this code, and everything was working well, but part of the assignment is that it must include nested loops. Once I added the nested while loop, which is basically an if statement, my life was ruined. I am trying to nest a loop in the code that will basically tell the compiler that if the value "loopVol" were to exceed the value of "final" after adding an increment, to run the program for the "final". How can I do that?
Example:
initial = 10 final = 123 increment = 10
as of now, the program would stop at 120, but I want to nest a loop that will tell the compiler to calculate at the final if this happens.
What output would you expect from this program?" The output was not what I expected. I've psuedo-coded this out and I'm still missing something.
Code:
#include <stdio.h> int main () { int numbers[10] = { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; int i, j; }
[code]....
The output: Code: 1 1 2 4 8 16 32 64 128 256 So when I look at this first loop I see that j = 0, which is less than 10, so then the program statement should commence, which is another for loop. So in this inner for loop I see that i = 0, which is not less than j, so this loop should terminate. Then the value of j increments by 1 and the first go around of the loop has completed.
Now I see that j = 1, so this is less than 10, and the inner for loop commences once again. This time though, i actually is less than j, so numbers[1] = numbers[1] + numbers [0], or numbers[1] = 0 + 1. Now the value of i is incremented by 1 and the first go around of this inner loop has completed. Then the value of j increments by 1 and another go around of that loop has completed.
So now j = 2, i = 1, and numbers[2] ( which is 0 ) = numbers[2] + numbers[1], or numbers[2] = 0 + 1. I was expecting the output to be an array full of 1's. However this is not the case..
it occupied too much memory,i wanted to clear them(both outer map and inner map) ,some one told me you just need to call m_mapRISCP.clear(),then the mapSection (inner map) will be cleared automaticly,in other words, m_mapRISCP.clear() will clear both outer map and inner map.
I'm working on a project involving nested classes and structs like this:
Code: class A { public:class B { public:f() {A::C* iCanDoThis; //no errors. iCanAlsoDoThis->root->.... //this also works fine.}private:A::C* iCannotDoThis //this is what I would like to do. Has errors A* iCanAlsoDoThis;};private:struct C {..data..};
C* root;};
Is it possible make a pointer to struct C a private member of class B?
So I think I am having syntactical problem with my code.
Code: int main() { vector<int> ivec; int score; [Code] ....
I get an error from my compiler on the ?10th? line (Nested condition line) that says |19|error: invalid operands of types 'int' and '<unresolved overloaded function type>' to binary 'operator<<'|
The purpose of the program is to take input and store it in a vector and then change the value to be between 1-6. I made this for the purpose of learning about nested conditional operations.
Note: In this case, the values of x,y and z is integers from 0 to 3 inclusive.
For 3-dimensional space above, actually the code had run through 3 nested "for" loops.
Question: Above code works for 3-dimensional space. How to generalize the code, so that it works also for N-dimensional space, where N is an arbitrary integer?
So in class our teacher assigned us a program where we have to use nested for loops to creates triangles. How does the 2nd for loop print more than 1 star? since the for loop will only run the cout 1 time until it gets to the escape sequence, how does it print more than 1 star on a line? this is what is confusing me. I feel like if i can grasp the understanding of that and what the for loops are doing i can finish the rest of this program with ease
#include<iostream> using namespace std; int main()
