Density Functional Theory (DFT) is a very useful tool for studying fluids in any external potential, based on expressing the Grand-potential as a functional of the density function. Once found the Grand-potential expression thermodynamic quantities can be obtained as functional derivatives of it in a very intuitive and formally correct way. Unfortunately for real problem computation have to be done numerically after some practicle approximations. During my project presentation I will discuss a little DFT and show the result that this theory gives for the Hard Rods model (Hard spheres in 1D) and discuss them for 2 different external potentials.