new repo

Makefile

@@ -0,0 +1,35 @@
+CC=gcc
+CXX=g++
+RM=rm -f
+CP=cp
+MKDIR=mkdir -p
+CPPFLAGS=-Wall -O2 -std=c++11
+LDFLAGS=
+LDLIBS=
+
+TOOL=ranlin
+SRCS=main.cpp
+OBJS=$(subst .cpp,.o,$(SRCS))
+
+all: $(TOOL)
+
+$(TOOL): $(OBJS)
+	$(CXX) $(LDFLAGS) -o $(TOOL) $(LDLIBS) $(OBJS) 
+
+depend: .depend
+
+.depend: $(SRCS)
+	$(RM) ./.depend
+	$(CXX) $(CPPFLAGS) -MM $^>>./.depend;
+
+clean:
+	$(RM) $(OBJS)
+
+dist-clean: clean
+	$(RM) *~ ./.depend $(TOOL)
+
+install:
+	$(RM) ~/bin/$(TOOL)
+	$(CP) $(TOOL) ~/bin/
+
+include .depend

main.cpp

@@ -0,0 +1,40 @@
+//
+//  main.cpp
+//  ranlin
+//
+//  Created by Bob Polis on 05-03-15.
+//  Copyright (c) 2015 Thalictrum. All rights reserved.
+//
+
+#include <iostream>
+#include <fstream>
+#include <string>
+#include <random>
+using namespace std;
+
+double next_random() {
+    static random_device dev;
+    static default_random_engine engine {dev()};
+    static uniform_real_distribution<double> dist {0, 1};
+    return dist(engine);
+}
+
+string random_line_from_file(istream& file) {
+    string line;
+    string result;
+    for (int nr {1}; getline(file, line); ++nr) {
+        if (next_random() * nr < 1.0) {
+            result = line;
+        }
+    }
+    return result;
+}
+
+int main(int argc, const char * argv[]) {
+    if (argc > 1) {
+        ifstream infile {argv[1]};
+        cout << random_line_from_file(infile) << '\n';
+    } else {
+        cout << random_line_from_file(cin) << '\n';
+    }
+}