CODEWITHSUNDEEP
c++lambda
saccharine
saccharine

Reputation: 904

C++ sort using lambda errors

I'm trying to sort an array using a lambda to use another array in the comparison function. Inside a larger function, I have this code:

std::sort(arr.begin(), arr.end(),[] (int& a, int& b)
{       
    return (*i)[a] < (*i)[b];
});

I get the following errors in the containing function:

mcmc.cpp:139: error: expected primary-expression before ‘[’ token
mcmc.cpp:139: error: expected primary-expression before ‘]’ token
mcmc.cpp:139: error: expected primary-expression before ‘int’
mcmc.cpp:139: error: expected primary-expression before ‘int’

When compiling, I'm including the -std=c++0x option as well.

I'm confused about what's going on. For some reason, it doesn't seem to recognize my syntax as valid. I did a yum update just in case, but it still seems as if it just doesn't recognize the use of lambdas.

Upvotes: 3

Views: 2208

Answers (1)

syam
syam

Reputation: 15069

C++11 lambdas require GCC/G++ 4.5 at least, they won't work with G++ 4.4.

See http://gcc.gnu.org/projects/cxx0x.html (or, since it is down right now, the cached version).

Upvotes: 8

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