diff --git a/src/bound_pop.cpp b/src/bound_pop.cpp
index b0f6caa..0eaf0c5 100644
--- a/src/bound_pop.cpp
+++ b/src/bound_pop.cpp
@@ -26,13 +26,12 @@
 
 #include <OptionParser.hpp>
 
-#include <unistd.h>
-
 #include <algorithm>
+#include <cstdint>
 #include <filesystem>
 #include <fstream>
 #include <iostream>
-#include <random>
+#include <random>  // std::mt19937
 #include <stdexcept>
 #include <string>
 #include <vector>
@@ -43,8 +42,8 @@ using std::isfinite;
 using std::min;
 using std::mt19937;
 using std::runtime_error;
-using std::setprecision;
 using std::string;
+using std::uint32_t;
 using std::vector;
 
 static void
@@ -104,7 +103,7 @@ bound_pop_main(const int argc, const char *argv[]) {
     size_t n_bootstraps = 500;
     double c_level = 0.95;
     size_t max_iter = 100;
-    uint64_t seed = 408;
+    uint32_t seed = 408;
 
     const string description = R"(
 Estimate a bound on the size of the underlying population based on
@@ -323,7 +322,6 @@ counts of observed species in an initial sample.
       vector<double> quad_estimates;
 
       // setup rng
-      srand(time(0) + getpid());
       mt19937 rng(seed);
 
       // hist may be sparse, to speed up bootstrapping
diff --git a/src/c_curve.cpp b/src/c_curve.cpp
index 9676a5b..271c204 100644
--- a/src/c_curve.cpp
+++ b/src/c_curve.cpp
@@ -29,17 +29,11 @@
 #include <smithlab_os.hpp>
 #include <smithlab_utils.hpp>
 
-#include <sys/types.h>
-#include <unistd.h>
-
 #include <algorithm>
-#include <array>
-#include <cmath>
-#include <cstddef>
+#include <cstddef>  // std::size_t
 #include <cstdint>
 #include <filesystem>
 #include <fstream>
-#include <iomanip>
 #include <iostream>
 #include <numeric>
 #include <random>
@@ -47,20 +41,15 @@
 #include <vector>
 
 using std::accumulate;
-using std::array;
 using std::cbegin;
 using std::cend;
 using std::cerr;
 using std::endl;
-using std::isfinite;
-using std::max;
-using std::min;
 using std::mt19937;
-using std::runtime_error;
-using std::setprecision;
 using std::size;
+using std::size_t;
 using std::string;
-using std::uint64_t;
+using std::uint32_t;
 using std::vector;
 
 template <typename T>
@@ -83,7 +72,7 @@ c_curve_main(const int argc, const char *argv[]) {
     bool PAIRED_END = false;
     bool HIST_INPUT = false;
     bool VALS_INPUT = false;
-    uint64_t seed = 408;
+    uint32_t seed = 408;
 
     string outfile;
     string histogram_outfile;
@@ -158,7 +147,6 @@ instead resamples from the given data.
     /******************************************************************/
 
     // Setup the random number generator
-    srand(time(0) + getpid());  // random seed
     mt19937 rng(seed);
 
     vector<double> counts_hist;
@@ -198,7 +186,7 @@ instead resamples from the given data.
       n_reads = load_counts_BED_se(input_file_name, counts_hist);
     }
 
-    const size_t max_observed_count = counts_hist.size() - 1;
+    const size_t max_observed_count = size(counts_hist) - 1;
     const double distinct_reads =
       accumulate(cbegin(counts_hist), cend(counts_hist), 0.0);
 
diff --git a/src/common.cpp b/src/common.cpp
index 063e2eb..a0d1448 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -38,6 +38,8 @@
 
 using std::array;
 using std::begin;
+using std::cbegin;
+using std::cend;
 using std::cerr;
 using std::end;
 using std::endl;
@@ -46,7 +48,7 @@ using std::mt19937;
 using std::runtime_error;
 using std::size_t;
 using std::string;
-using std::uint64_t;
+using std::uint32_t;
 using std::vector;
 
 double
@@ -110,7 +112,7 @@ interpolate_distinct(const vector<double> &hist, const size_t N, const size_t S,
       numer[i] = exp(x - denom) * hist[i];
     }
   }
-  return S - accumulate(begin(numer), end(numer), 0);
+  return S - accumulate(cbegin(numer), cend(numer), 0);
 }
 
 static void
@@ -136,7 +138,7 @@ extrap_single_estimate(const bool VERBOSE, const bool allow_defects,
   yield_estimate.clear();
 
   const double vals_sum = get_counts_from_hist(hist);
-  const double initial_distinct = accumulate(begin(hist), end(hist), 0.0);
+  const double initial_distinct = accumulate(cbegin(hist), cend(hist), 0.0);
 
   // interpolate complexity curve by random sampling w/out replacement
   const size_t upper_limit = vals_sum;
@@ -197,7 +199,7 @@ extrap_single_estimate(const bool VERBOSE, const bool allow_defects,
 
 void
 extrap_bootstrap(const bool VERBOSE, const bool allow_defects,
-                 const uint64_t seed, const vector<double> &orig_hist,
+                 const uint32_t seed, const vector<double> &orig_hist,
                  const size_t n_bootstraps, const size_t orig_max_terms,
                  const int diagonal, const double bin_step_size,
                  const double max_extrap, const size_t max_iter,
@@ -206,11 +208,10 @@ extrap_bootstrap(const bool VERBOSE, const bool allow_defects,
   bootstrap_estimates.clear();
 
   // setup rng
-  srand(time(0) + getpid());
   mt19937 rng(seed);
 
   const double initial_distinct =
-    std::accumulate(begin(orig_hist), end(orig_hist), 0.0);
+    std::accumulate(cbegin(orig_hist), cend(orig_hist), 0.0);
 
   vector<size_t> orig_hist_distinct_counts;
   vector<double> distinct_orig_hist;
@@ -236,7 +237,7 @@ extrap_bootstrap(const bool VERBOSE, const bool allow_defects,
       hist.pop_back();
 
     // compute complexity curve by random sampling w/out replacement
-    const size_t distinct = accumulate(begin(hist), end(hist), 0.0);
+    const size_t distinct = accumulate(cbegin(hist), cend(hist), 0.0);
     size_t curr_sample_sz = bin_step_size;
     while (curr_sample_sz < sample_vals_sum) {
       yield_vector.push_back(
@@ -364,7 +365,7 @@ resample_hist(mt19937 &gen, const vector<size_t> &vals_hist_distinct_counts,
   vector<uint32_t> sample_distinct_counts_hist(hist_size, 0);
 
   const uint32_t distinct =
-    accumulate(begin(distinct_counts_hist), end(distinct_counts_hist), 0.0);
+    accumulate(cbegin(distinct_counts_hist), cend(distinct_counts_hist), 0.0);
 
   multinomial(gen, distinct_counts_hist, distinct, sample_distinct_counts_hist);
 
diff --git a/src/common.hpp b/src/common.hpp
index 357c84c..0ab08b8 100644
--- a/src/common.hpp
+++ b/src/common.hpp
@@ -46,7 +46,7 @@ extrap_single_estimate(const bool VERBOSE, const bool allow_defects,
 
 void
 extrap_bootstrap(const bool VERBOSE, const bool allow_defects,
-                 const std::uint64_t seed, const std::vector<double> &orig_hist,
+                 const std::uint32_t seed, const std::vector<double> &orig_hist,
                  const std::size_t n_bootstraps,
                  const std::size_t orig_max_terms, const int diagonal,
                  const double bin_step_size, const double max_extrap,
diff --git a/src/gc_extrap.cpp b/src/gc_extrap.cpp
index 0c5b16e..ee0942c 100644
--- a/src/gc_extrap.cpp
+++ b/src/gc_extrap.cpp
@@ -26,6 +26,8 @@
 #include <OptionParser.hpp>
 
 #include <algorithm>
+#include <cstddef>
+#include <cstdint>
 #include <filesystem>
 #include <fstream>
 #include <iostream>
@@ -39,7 +41,9 @@ using std::cerr;
 using std::endl;
 using std::min;
 using std::runtime_error;
+using std::size_t;
 using std::string;
+using std::uint32_t;
 using std::vector;
 
 // ADS: functions same, header different (above and this one)
@@ -92,7 +96,7 @@ gc_extrap_main(const int argc, const char *argv[]) {
     bool SINGLE_ESTIMATE = false;
     double max_extrap = 1.0e12;
     size_t n_bootstraps = 100;
-    uint64_t seed = 408;
+    uint32_t seed = 408;
     bool allow_defects = false;
 
     bool NO_SEQUENCE = false;
diff --git a/src/lc_extrap.cpp b/src/lc_extrap.cpp
index dfcaa5f..120a1b9 100644
--- a/src/lc_extrap.cpp
+++ b/src/lc_extrap.cpp
@@ -21,13 +21,12 @@
 #include "lc_extrap.hpp"
 
 #include "common.hpp"
-
 #include "load_data_for_complexity.hpp"
 
-#include "OptionParser.hpp"
+#include <OptionParser.hpp>
 
 #include <algorithm>
-#include <cstddef>
+#include <cstddef>  // std::size_t
 #include <cstdint>
 #include <filesystem>
 #include <fstream>
@@ -48,7 +47,6 @@ using std::size_t;
 using std::string;
 using std::to_string;
 using std::uint32_t;
-using std::uint64_t;
 using std::vector;
 
 int
@@ -68,7 +66,7 @@ lc_extrap_main(const int argc, const char **argv) {
     size_t n_bootstraps = 100;
     int diagonal = 0;
     double c_level = 0.95;
-    uint64_t seed = 408;
+    uint32_t seed = 408;
 
     /* FLAGS */
     bool verbose = false;
diff --git a/src/load_data_for_complexity.cpp b/src/load_data_for_complexity.cpp
index 79c17cf..02ee34f 100644
--- a/src/load_data_for_complexity.cpp
+++ b/src/load_data_for_complexity.cpp
@@ -20,8 +20,8 @@
 
 #include "load_data_for_complexity.hpp"
 
-#include "GenomicRegion.hpp"
-#include "MappedRead.hpp"
+#include <GenomicRegion.hpp>
+#include <MappedRead.hpp>
 
 #ifdef HAVE_HTSLIB
 #include "bam_record_utils.hpp"  // from dnmtools
@@ -29,11 +29,9 @@
 #include <htslib_wrapper.hpp>
 #endif  // HAVE_HTSLIB
 
-#include <unistd.h>
-
-#include <algorithm>  // std::min
-#include <cstddef>
-#include <cstdint>
+#include <algorithm>   // std::min
+#include <cstddef>     // std::size_t
+#include <cstdint>     // std::uint32_t
 #include <functional>  // std::greater
 #include <iostream>
 #include <queue>
@@ -51,7 +49,7 @@ using std::runtime_error;
 using std::size;
 using std::size_t;
 using std::string;
-using std::uint64_t;
+using std::uint32_t;
 using std::unordered_map;
 using std::vector;
 
@@ -413,11 +411,9 @@ SplitMappedRead(const MappedRead &inputMR, mt19937 &generator,
 }
 
 size_t
-load_coverage_counts_MR(const string &input_file_name, const uint64_t seed,
+load_coverage_counts_MR(const string &input_file_name, const uint32_t seed,
                         const size_t bin_size, const size_t max_width,
                         vector<double> &coverage_hist) {
-  srand(time(0) + getpid());
-  // Runif runif(rand());
   std::mt19937 generator(seed);
 
   std::ifstream in(input_file_name);
@@ -465,10 +461,9 @@ load_coverage_counts_MR(const string &input_file_name, const uint64_t seed,
 }
 
 size_t
-load_coverage_counts_GR(const string &input_file_name, const uint64_t seed,
+load_coverage_counts_GR(const string &input_file_name, const uint32_t seed,
                         const size_t bin_size, const size_t max_width,
                         vector<double> &coverage_hist) {
-  srand(time(0) + getpid());
   std::mt19937 generator(seed);
 
   std::ifstream in(input_file_name);
@@ -724,10 +719,9 @@ update_coverage_hist(const T &curr, const T &prev, vector<double> &counts_hist,
 // first mate for each mapped read
 size_t
 load_coverage_counts_BAM(const uint32_t n_threads, const string &inputfile,
-                         const uint64_t seed, const size_t bin_size,
+                         const uint32_t seed, const size_t bin_size,
                          const size_t max_width,
                          vector<double> &coverage_hist) {
-  srand(time(0) + getpid());
   std::mt19937 generator(seed);
 
   bamxx::bam_tpool tp(n_threads);
diff --git a/src/pop_size.cpp b/src/pop_size.cpp
index 0677be5..e5ca1df 100644
--- a/src/pop_size.cpp
+++ b/src/pop_size.cpp
@@ -26,6 +26,7 @@
 #include <OptionParser.hpp>
 
 #include <algorithm>
+#include <cstddef>  // std::size_t
 #include <cstdint>
 #include <filesystem>
 #include <fstream>
@@ -41,8 +42,10 @@ using std::count_if;
 using std::endl;
 using std::min;
 using std::runtime_error;
+using std::size_t;
 using std::string;
 using std::to_string;
+using std::uint32_t;
 using std::vector;
 
 int
@@ -63,7 +66,7 @@ pop_size_main(const int argc, const char *argv[]) {
     size_t n_bootstraps = 100;
     int diagonal = 0;
     double c_level = 0.95;
-    uint64_t seed = 408;
+    uint32_t seed = 408;
 
     /* FLAGS */
     bool verbose = false;