#include "ezinc.h"/* global variables -- but private to this file */static double delay, width=0, cdtds;/* prompt user for source-function width and delay. */void ezIncInit(Grid *g){  cdtds = Cdtds;    printf("Enter delay: ");  scanf(" %lf",&delay);  printf("Enter width: ");  scanf(" %lf",&width);  return;}/* calculate source function at given time and location */double ezInc(double time, double location) {  if (width<=0) {    fprintf(stderr,       "ezInc: must call ezIncInit before ezInc.\n"       "       Width must be positive.\n");    exit(-1);  }  return exp( -pow( (time - delay - location/cdtds)/width, 2) );}