modelling interarrival times

Hello,

I have written a c program to generate interarrival times based on exponential distribution and store it as a .mif file. Here I am generating inter arrival time based on negative exponential distribution function. The packet last for 1.2 micro seconds and my clock is 6.4ns duration. So that it can used to initialize my RAM. Would like to know your feedback and if any improvements can be made. thanks

# include <stdio.h>
# include <stdlib.h>
# include <math.h>
# define rate 1
# define width 3
# define depth 64
int main()
{
double u,delta_t;
int i,delta;
FILE *fp = fopen("negexpdata.mif","w");
fprintf(fp,"WIDTH=%d;\n",width);
fprintf(fp,"DEPTH=%d;\n\n",depth);
fprintf(fp,"ADDRESS_RADIX=UNS;\n");
fprintf(fp,"DATA_RADIX=UNS;\n\n");
fprintf(fp,"CONTENT BEGIN\n");
for(i=0;i<depth;i++)
{
u = (double) rand()/ (double) RAND_MAX;
//delta_t = -log(u)/rate;
delta_t = -(1200 * log2(1-u))/6.4;
delta= (int)delta_t;
fprintf(fp,"\t%d\t:\t%d\n",i,delta);
}
fprintf(fp,"END;\n");
fclose(fp);
return(0);
}