Chapter 4

Author: Kevin Languasco

.gitignore

@@ -1,2 +1,3 @@
 .ycm_extra_conf.py
 .color_coded
+_vimrc_local.vim

3-working_with_batches_of_data/median.cpp

@@ -28,10 +28,10 @@ int main() {
     while (cin >> x) {
         homework.push_back(x);
     }
-    
+
     typedef vector<double>::size_type vec_sz;
     vec_sz size = homework.size();
-    
+
     if (size==0) {
         cout << endl << "You must enter your grades. "
             "Please try again." << endl;

4-organizing_programs_and_data/grades

@@ -0,0 +1,83 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+#include <stdexcept>
+#include <string>
+#include <ios>
+#include <iomanip>
+
+using std::vector;
+using std::sort;
+using std::domain_error;
+using std::istream;
+using std::string;
+using std::cin;
+using std::cout;
+using std::endl;
+using std::setprecision;
+using std::streamsize;
+
+double grade(double midterm, double final, double homework) {
+    return 0.2 * midterm + 0.4 * final + 0.4 * homework;
+}
+
+double median(vector<double> vec) {
+    typedef vector<double>::size_type vec_sz;
+    vec_sz size = vec.size();
+    if (size==0)
+        throw domain_error("median of an empty vector");
+
+    sort(vec.begin(), vec.end());
+
+    vec_sz mid = size/2;
+
+    return size % 2 == 0 ? (vec[mid] + vec[mid-1]) /2 : vec[mid];
+}
+
+// overloading
+double grade(double midterm, double final, const vector<double>& hw) {
+    if (hw.size() == 0)
+        throw domain_error("student has done no homework");
+    return grade(midterm, final, median(hw));
+}
+
+istream& read_hw(istream& in, vector<double>& hw) {
+    if (in) {
+        // get rid of previous contents
+        hw.clear();
+        // read the homework grades
+        double x;
+        while (in>>x)
+            hw.push_back(x);
+        // clear the stream so that input will work for the next student
+        in.clear();
+    }
+    return in;
+}
+
+int main() {
+    cout << "Please enter your first name: ";
+    string name;
+    cin >> name;
+    cout << "Hello, " << name << "!" << endl;
+    cout << "Please enter your midterm and final exam grades: ";
+    double midterm, final;
+    cin >> midterm >> final;
+    cout << "Enter all your homework grades, "
+        "followed by end-of-file: ";
+    vector<double> homework;
+    read_hw(cin, homework);
+    try {
+        double final_grade = grade(midterm, final, homework);
+        streamsize prec = cout.precision();
+        cout << "Your final grade is " << setprecision(3)
+            << final_grade << setprecision(prec) << endl;
+    } catch (domain_error) {
+        cout << endl << "You must enter your grades. "
+            "Please try again." << endl;
+        return 1;
+    }
+    return 0;
+}
+
+

4-organizing_programs_and_data/grades.cpp

@@ -0,0 +1,4 @@
+CXX = clang++
+C = clang++
+
+all: grades