//To calculate the minimum energy
n = 1;     //for minimum energy
h = 6.626*10^-34;      //planck's constant, J sec
m = 9.1*10^-31;      //mass of electron, kg
L = 4*10^-10;     //side of box, m
E1 = h^2*n^2/(8*m*L^2);      //lowest energy, J
printf("energy of electron in J is");
disp(E1);

//answer given in the book is wrong