code4.m

%declare basic variables 
gamma = 1.4;
p4 = 2.0; 
p1 = 1.0; 
rho4 = 2.0; 
rho1 = 1.0; 
imax = 41; 
xmin = 0; 
xmax = 2.; 
dx = (xmax-xmin)/(imax-1);