change mode in linux

C++
For changing permissions mode of files as "file.exe" follow next examples idea:
chmod file.exe ugo+x #Add x:execute permissions to u:user g:gropu and o:others
chmod file.exe o-rw  #Remove r:read and w:write permissions to o:others
chmod file.exe +rwx  #Add all r:read, w:wirte and x:execute permissions to all.
Source

Also in C++: