Vector c++ 98 error

Question

so ive been reading multiple (and resent) c++ books and learning about vectors and they all are telling me to define a vector like this:

 vector<int> v1 = {4 ,3 ,5}; 

however when i compile it (Im using gnu gcc compiler in codeblocks) it comes up with this error

in c++ 98 'v1' must be initialized by constructor not by '{...}' and i also get another one underneath that that sais: could not convert '{4, 3, 5}' from 'brace enclosed initializer list' to 'std::vector v1'

if you could help me it'd be much appreciated. And i did include the vector library.

Answer 1

Initialization used by you is calledinitializer list and it is supported c++11 onwards.

To ensure code is compiled, use C++11 or later -std option. Or in general, don't use C++98 .

If you are using g++, please read: Compiling C++11 with g++

---

From comments OP is using codeblocks. You can use the following steps before hitting the compile button: (Source: How can I add C++11 support to Code::Blocks compiler? )

1. Go to Toolbar -> Settings -> Compiler
2. In the "Selected compiler" drop-down menu, make sure "GNU GCC Compiler" is selected
3. Below that, select the "compiler settings" tab and then the "compiler flags" tab underneath
4. In the list below, make sure the box for "Have g++ follow the C++11 ISO C++ language standard [-std=c++11]" is checked
5. Click OK to save

Answer 2

The C++98 Standard does not support initializer lists to initialize standard containers.

Try to set appropriate compiler options to compile the code according to the C++ 2011 Standard.

Another approach is to add elements to the vector individually like

std::vector<int> v1;
v1.reserve( 3 );

v1.push_back( 4 );
v1.push_back( 3 );
v1.push_back( 5 );

Instead of the member function push_back you can use overloaded operator += . For example

std::vector<int> v1;
v1.reserve( 3 );

v1 += 4;
v1 += 3;
v1 += 5;

Or to use an array like

const size_t N = 3;
int a[N] = { 4, 3, 5 };
std::vector<int> v1( a, a + N );

Answer 3

Compile with the -std=c++11 compiler option at the end of the line in the makefile.

So for example:

g++ -ggdb -O0 -c ENiX_Chocky.cpp -std=c++11
g++ -ggdb -O0 -c ENiX_NLPTest.cpp -std=c++11
...

Then when you link, use the -std=c++11 option again:

g++ -ggdb -O0 ENiX_Chocky.cpp ENiX_NLPTest.cpp -o CLINLPTest.cpp -std=c++11

The error will immediately disappear.

Answer 4

Follow these steps if you are using Codeblocks:

1.Go to Toolbar -> Settings -> Compiler

2.In the "Selected compiler" drop-down menu, make sure "GNU GCC Compiler" is selected.

3.Below that, select the "compiler settings" tab and then the "compiler flags" tab underneath.

4.In the list below, make sure the box for "Have g++ follow the C++11 ISO C++ language standard [-std=c++11]" is checked.

5.Click OK to save

Answer 5

Intilizer_list only supported on c++11 onwards.

Compile your program as below :

1. If you are using c++11 features then follow -std=c++11 option;
2. If you are using c++14 features then follow -std=c++14 option.

EX:

gcc Temp.cpp -std=c++11 -o out_put
gcc Temp.cpp -std=c++14 -o out_put