g++: expected primary-expression before ‘[’ token

Question

I am trying to find if all the elements of a vector y is equal to 1. The following code works fine in Visual Studio but with g++ in linux (g++ -std=c++0x) it gives me this error: expected primary-expression before ‘[’ token

bool x = all_of(y.begin(), y.end(), [](unsigned char j) {return j == 1;});

Any help would be appreciated.

My gcc version is: g++ (GCC) 4.4.7 20120313 (Red Hat 4.4.7-17)

• NathanOliver: What version of g++ are you using?
• drescherjm: Are you sure you enabled c++11? Or perhaps you have an ancient version of g++.
• Lightness Races in Orbit: -std=c++0x This suggests an old compiler. What version of GCC is that?
• molbdnilo: @Ali That's almost five years old. Time to upgrade.
• Arnav Borborah: Use an actual function/function pointer

Answer 1

Lambdas are not supported in GCC 4.4.

Upgrade your compiler. You need GCC 4.5 or higher, but get to modern times if you can.

• user4581301: @GillBates you mock, but Turbo C++ is coming back, man. Just like Disco.

Answer 2

Your compiler not support lambda expression. Compilers do not support all features that come with C++11 or new incoming standards. Therefore you need to check which standards the compiler supports. Screenshot of compilation on GCC 4.4.7

You can see if I select gcc-4.4.7 same error( lambda expression error) but if I select gcc-4.5.3

Screenshot of compilation on GCC 4.5.2

No error. In summary, You have to change your compiler(>= gcc-4.5 ) to use lamda expression.

C++ Standards Support in GCC

Answer 3

Lambdas are not supported in GCC 4.4. You can upgrade your compiler to version 4.5 or above, or use a function:

bool compFun(int i) {
 return i == 1;
}
...
bool res = all_of(a.begin(), a.end(), compFun);

Here is a live example.