dictionary.cpp is a c++11 version dictionary2.cpp is a c++03 version Prereqs: ICU4C needs to be installed http://download.icu-project.org/files/icu4c/56.1/icu4c-56_1-src.tgz ./configure make make install OR yum install icu libicu libicu-devel c++11 compilation: clang++ -O3 dictionary.cpp -L/usr/local/lib -licui18n -licuuc -licudata -licuio -o dictionary c++ -O3 -std=c++11 -stdlib=libc++ dictionary.cpp -L/usr/local/lib -licui18n -licuuc -licudata -licuio -o dictionary c++03 compilation clang++ -O3 dictionary2.cpp -L/usr/local/lib -licui18n -licuuc -licudata -licuio -o dictionary2 c++ -O3 -stdlib=libc++ dictionary2.cpp -L/usr/local/lib -licui18n -licuuc -licudata -licuio -o dictionary2 Execution: ./dictionary words.txt ./dictionary2 words.txt Word list format: 0 <word1> 1 <word2> ... 1920 <word1921> ...