产生方波的c语言文件，可以产生不同频率的方波，不同波长，不同时间长度。-c file for wave

mpi fortran wave equation solver code !cc MAIN is the main program for WAVE_MPI. !c !c Discussion: !c !c WAVE_MPI solves the wave equation in parallel using MPI. !c !c Discretize the equation for u(x,t): !c d^2 u/dt^2 - c^2 * d^2 u