cocos2d-x for android on the issue of string functions

            
Just at the official website of cocos2dx3.0 sdk, examples of program compiler, able to run, but once using c + +11's stoi, to_string other functions will compile error, suggesting that the function can not be found, the error log is as follows:
jni / / / Classes / AppDelegate.cpp:.... 83:14: error: 'stoi' was not declared in this scope
stoi ("11");

Tangled day, using the string class in the code is not the problem, it is that several functions can not be found, these are the c + + standard function, why android is not use it, do not know what the configuration is not wrong, incidentally one, android ndk using r9b, NDK_TOOLCHAIN ​​also 4.8, c + +11 support new features. Seeking solutions ~ ~ ~