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Vector Question 17 Years Ago by Jennifer84 … would look like this: [code]std::vector<string> StdVector; StdVector[0] = "comboBox1->SelectedItem->ToString()"; [/code] My…;comboBox1->SelectedItem->ToString()"[/COLOR] out ? [code] Box1 = StdVector[0]; [/code] Undefined behaviour accessing uninitialised data? 11 Years Ago by triumphost …**`. My results were: http://stackoverflow.com/questions/20863478/class-using-stdvector-allocation-slower-than-pointer-allocation-by-a-lot Now I… Re: vector operations 14 Years Ago by jonsca You can use an iterator for what you are trying to describe (see the second post of [url]http://stackoverflow.com/questions/3221812/sum-of-elements-in-a-stdvector[/url]). Or you could use std::accumulate ([url]http://www.cplusplus.com/reference/std/numeric/accumulate/[/url] or the above link) Re: Dynamic Array Question 12 Years Ago by vijayan121 …/stl/article.php/c4027/C-Tutorial-A-Beginners-Guide-to-stdvector-Part-1.htm > I am using Dev-CPP 4… Re: Custom Allocator for shared memory. 12 Years Ago by mike_2000_17 … thread](http://stackoverflow.com/questions/5958572/how-can-i-avoid-stdvector-to-initialize-all-its-elements/). Scott Meyers talks about allocators… Re: "unresolved identifier 'array'" using array class 12 Years Ago by yxBen …://stackoverflow.com/questions/11400090/c-why-initializer-list-behavior-for-stdvector-and-stdarray-are-different?rq=1) [C++ Standard Core Language… Re: How can i edit this code to accept more than one account 10 Years Ago by ddanbe If I would implement more than 3 accounts I would use a vector of Account. Here's a good [tutorial](http://www.codeguru.com/cpp/cpp/cpp_mfc/stl/article.php/c4027/C-Tutorial-A-Beginners-Guide-to-stdvector-Part-1.htm) about vector. Re: Vector Question 17 Years Ago by vijayan121 it would be easier (and also more efficient) if you use a cliext::vector<> instead of a std::vector<> note: requires VC++ 9 (2008) [CODE]#include <cliext/vector> using namespace cliext ; // ... { // ... vector< String^ >^ vec = gcnew vector< String^ > ; vec->push_back( comboBox1->SelectedItem->… Re: Vector Question 17 Years Ago by Jennifer84 Thank you. I do have Visual 9.0 2008 so this works though. I will give 2 examples of what I am doing. The first one works but what I want is to replace it with the second. Both examples compiles but the second example with the Array terminates the program when I am running it. I keep wonder why and what the differences are ? As seen I am doing… Re: Vector Question 17 Years Ago by vijayan121 [CODE]#include <cliext/vector> using namespace cliext ; // ... // create an [COLOR="Red"]empty[/COLOR] vector cliext::vector< String^ >^ Box1 = gcnew cliext::vector< String^ >; // this will not work; [COLOR="Red"]there is no space in the vector[/COLOR] // [COLOR="Red"]Box1[0][/COLOR] = comboBox1->… Re: Vector Question 17 Years Ago by Jennifer84 Thanks, vijayan121. That did work fine ! I forgot about the space that you mentioned also. Re: Vector Question 17 Years Ago by Jennifer84 I have a wondering here. Is it correct to do pushback like this: [code] Box1->push_back( comboBox1->SelectedItem->ToString() ) ; Box1->push_back( comboBox2->SelectedItem->ToString() ) ; [/code] Do comboBox1 get place Box1[0] and do comboBox2 get place Box1[1] in this case when writing them under eachother like this ?… Re: Vector Question 17 Years Ago by mitrmkar Could it be that comboBox2->SelectedItem is a NULL reference? Calling Box1->push_back() like you do is OK. Re: Vector Question 17 Years Ago by Jennifer84 Yes it was depending on that. The selected Item was a NULL reference. I changed SelectedTiem to this instead and then it is ok if it is a "NULL reference" [code] Box1->push_back( comboBox2->Text->ToString() ) ; [/code] [QUOTE=mitrmkar;547201]Could it be that comboBox2->SelectedItem is a NULL reference? Calling Box1… Re: Undefined behaviour accessing uninitialised data? 11 Years Ago by Moschops What do you mean by "access" in this context? Re: Undefined behaviour accessing uninitialised data? 11 Years Ago by mike_2000_17 > Why is accessing data in an uninitialised array undefined behaviour? It's not really clear whether this is undefined behavior or not. If you **read** uninitialized data, you will read a garbage value, i.e., whatever arbitrary combination of bits that happens to be in that memory location at the time of the allocation. That's what's going to … Re: Undefined behaviour accessing uninitialised data? 11 Years Ago by deceptikon > Why is accessing data in an uninitialised array undefined behaviour? It really depends on where the array is defined. If it's a local array then it's undefined behavior just as accessing an uninitialized variable is undefined behavior. The contents of the array are indeterminate, which is the "official" reason for the undefined … Re: Undefined behaviour accessing uninitialised data? 11 Years Ago by triumphost I was just using the array as a matrix. I don't mind indeterminate values at all if I access an array with no initial value. I just don't want my program crashing or me doing something unsafe because of some undefined behaviour that I don't understand. I don't know why accessing an uninitialised array would be undefined. I understand indeterminate… Re: Undefined behaviour accessing uninitialised data? 11 Years Ago by deceptikon > I don't mind indeterminate values at all if I access an array with no initial value. I just don't want my program crashing because of some undefined behaviour that I don't understand. Those two sentences are contradictory. > I don't understand traps by just looking at it either. Imagine calling `abort`, but without the happy result for a… Re: Undefined behaviour accessing uninitialised data? 11 Years Ago by mike_2000_17 > The contents of the array are indeterminate, which is the "official" reason for the undefined behavior. There is obviously a gray zone between indeterminate values and undefined behavior. If it wasn't for trap representations (which I doubt still exist on any hardware at all), there would really be no reason why reading a variable …