I'm currently overviewing the new features of C++11 and for currently ununderstood reasons, some of them does not compile. I use gcc version 4.6.0 20100703 (experimental) (GCC) so according to the GNU GCC FAQ, all features I tried are supported . I tried to compile with both of std=c++0x and std=gnu++0x flags.
For instance, I wan't to use non member begin() and end(), in piece of code like :
#include <iostream>
#include <map>
#include <utility>
#include <iterator>
using namespace std;
int main ( ) {
map < string, string > alias;
alias.insert ( pair < string, string > ( "ll", "ls -al" ) );
// ... Other inserts
auto it = begin(alias);
while ( it != end(alias) ) {
//...
}
And I get,
nonMemberBeginEnd//main.cc:15:24: error: ‘begin’ was not declared in this scope
nonMemberBeginEnd//main.cc:15:24: error: unable to deduce ‘auto’ from ‘<expression error>’ // Ok, this one is normal.
nonMemberBeginEnd//main.cc:16:26: error: ‘end’ was not declared in this scope
Do I need to include special headers ?
My second (and last) question is weirder because It cannot depend on black magic hidden header that I might had not included.
The following code :
for ( auto kv : alias )
cout << kv.first << " ~ " << kv.second << endl;
Give me the following errors :
rangeFor/main.cc:15:17: error: expected initializer before ‘:’ token
I hope my questions are not off topic or too rookie for you guys and you'll help me find out what's wrong :D
It works on gcc 4.6.1:
#include <iostream>
#include <map>
#include <string>
int main(int argc, char** argv) {
std::map<std::string, std::string> alias = {{"key", "value"}};
for (auto kv: alias)
std::cout << kv.first << " ~ " << kv.second << std::endl;
auto it = begin(alias);
while (it != end(alias) ) {
std::cout << (*it).first << " ~ " << (*it).second << std::endl;
it++;
}
return EXIT_SUCCESS;
}
And the result:
# /opt/gcc-4.6.1/bin/g++-4.6 --std=c++0x test.cc -o test && ./test
key ~ value
key ~ value
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