Practicing C code
gcc - o main -g -Wall main.c permute.c

To use pow() API add -lm at the end of the gcc command.

git init # create new repo locally
git remote add origin https://github.com/vudoan2016/java.git

git add main.c permutation.c
git commit -m "Initial commit of string permutaion"
git push origin master

git remote -v
git diff --name-only
git status

Allow core file to be generated "ulimit -c unlimited"

On Windows: 
g++ new.cpp # to compile c++ files
gcc new.c # to compile c files