One easy way to install GCC higher version (which supports C++ 11 standard) in alternative directory (meaning without root privilege) is as follows:

• Download the latest GCC from http://gcc.gnu.org/
• Untar the package
• If you don’t have prerequisites for GCC (http://gcc.gnu.org/install/prerequisites.html), you need to the following steps:
  • Go to the source directory.
  • Do “contrib/download_prerequisites”.
• Create a new directory called “gcc-build” peer to the source directory.
• In “gcc-build”, perform “../gcc-XXX/configure –prefix=YYY”
• Do “make” and “make install”
• Add “YYY/lib” or “YYY/lib64” into your LD_LIBRARY_PATH and LD_RUN_PATH