标签：des style blog http io os ar for 2014
1.类型定义typedef
2.局部变量
3.格式化输出初涉
4.向量vector及基本方法
1.计算平均成绩
#include <iomanip>
#include <iostream>
#include <string>
using namespace std;
int main()
{
// ask for and read the student's name
cout << "Please enter your first name: ";
string name;
cin >> name;
cout << "Hello, " << name << "!" << endl;
// ask for and read the midterm and final grades
cout << "Please enter your midterm and final exam grades: ";
double midterm, final;
cin >> midterm >> final;
// ask for the homework grades
cout << "Enter all your homework grades, "
"followed by end-of-file: ";
// the number and sum of grades read so far
int count = 0;
double sum = 0;
// a variable into which to read
double x;
// invariant:
// we have read `count' grades so far, and
// `sum' is the sum of the first `count' grades
while (cin >> x)
{
++count;
sum += x;
}
// write the result
streamsize prec = cout.precision();
cout << "Your final grade is " << setprecision(3)
<< 0.2 * midterm + 0.4 * final + 0.4 * sum / count
<< setprecision(prec) << endl;
return 0;
}
结果:
2.计算成绩中值
#include <algorithm>
#include <iomanip>
#include <iostream>
#include <string>
#include <vector>
using namespace std;
int main()
{
// ask for and read the student's name
cout << "Please enter your first name: ";
string name;
cin >> name;
cout << "Hello, " << name << "!" << endl;
// ask for and read the midterm and final grades
cout << "Please enter your midterm and final exam grades: ";
double midterm, final;
cin >> midterm >> final;
// ask for and read the homework grades
cout << "Enter all your homework grades, "
"followed by end-of-file: ";
vector<double> homework;
double x;
// invariant: `homework' contains all the homework grades read so far
while (cin >> x)
homework.push_back(x);
// check that the student entered some homework grades
#ifdef _MSC_VER
typedef std::vector<double>::size_type vec_sz;
#else
typedef vector<double>::size_type vec_sz;
#endif
vec_sz size = homework.size();
if (size == 0)
{
cout << endl << "You must enter your grades. "
"Please try again." << endl;
return 1;
}
// sort the grades
sort(homework.begin(), homework.end());
// compute the median homework grade
vec_sz mid = size/2;
double median;
median = size % 2 == 0 ? (homework[mid] + homework[mid-1]) / 2
: homework[mid];
// compute and write the final grade
streamsize prec = cout.precision();
cout << "Your final grade is " << setprecision(3)
<< 0.2 * midterm + 0.4 * final + 0.4 * median
<< setprecision(prec) << endl;
return 0;
}
结果:
3.2
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
int main()
{
vector<int> integers;
cout << "Integers: ";
int x;
while (cin >> x)
integers.push_back(x);
if (integers.size() == 0)
{
cout << endl << "No integers!" << endl;
return 1;
}
sort(integers.rbegin(), integers.rend());
typedef vector<int>::size_type vec_sz;
cout << "1st quartile" << endl;
for (vec_sz i = 0; i < integers.size() / 4; ++i)
cout << integers[i] << endl;
cout << "2nd quartile" << endl;
for (vec_sz i = integers.size() / 4; i < integers.size() / 2; ++i)
cout << integers[i] << endl;
cout << "3rd quartile" << endl;
for (vec_sz i = integers.size() / 2; i < integers.size() * 3 / 4; ++i)
cout << integers[i] << endl;
cout << "4th quartile" << endl;
for (vec_sz i = integers.size() * 3 / 4; i < integers.size(); ++i)
cout << integers[i] << endl;
return 0;
}
结果:
3.3
#include <iostream>
#include <string>
#include <vector>
using namespace std;
int main()
{
typedef vector<string>::size_type vec_sz;
vector<string> words;
vector<int> counts;
cout << "Words: ";
string s;
while (cin >> s)
{
bool found = false;
for (vec_sz i = 0; i < words.size(); ++i)
{
if (s == words[i])
{
++counts[i];
found = true;
}
}
if (!found)
{
words.push_back(s);
counts.push_back(1);
}
}
for (vec_sz i = 0; i < words.size(); ++i)
cout << words[i] << " appeared " << counts[i] << " times" << endl;
return 0;
}
结果:
3.4
#include <iostream>
#include <string>
using namespace std;
int main()
{
typedef string::size_type str_sz;
string longest;
str_sz longest_length = 0;
string shortest;
str_sz shortest_length = 0;
cout << "Words: ";
string s;
while (cin >> s)
{
if (longest_length == 0 || s.size() > longest_length)
{
longest = s;
longest_length = s.size();
}
if (shortest_length == 0 || s.size() < shortest_length)
{
shortest = s;
shortest_length = s.size();
}
}
cout << "Longest: " << longest << endl;
cout << "Shortest: " << shortest << endl;
return 0;
}
3.5
#include <iomanip>
#include <iostream>
#include <string>
#include <vector>
using namespace std;
#define NUM_HOMEWORK 2
using std::vector;
int main()
{
vector<string> names;
vector<double> final_grades;
bool done = false;
while (!done)
{
// ask for and read the student's name
cout << "Please enter your first name: ";
string name;
cin >> name;
cout << "Hello, " << name << "!" << endl;
names.push_back(name);
// ask for and read the midterm and final grades
cout << "Please enter your midterm and final exam grades: ";
double midterm, final;
cin >> midterm >> final;
// ask for the homework grades
cout << "Enter both your homework grades, "
"followed by end-of-file: ";
// he number and sum of grades read so far
int count = 0;
double sum = 0;
// a variable into which to read
double x;
// invariant:
// we have read `count' grades so far, and
// `sum' is the sum of the first `count' grades
while (count < NUM_HOMEWORK)
{
++count;
cin >> x;
sum += x;
}
double final_grade = 0.2 * midterm + 0.4 * final + 0.4 * sum / count;
final_grades.push_back(final_grade);
cout << "More? (Y/N) ";
string s;
cin >> s;
if (s != "Y")
done = true;
}
for (vector<string>::size_type i = 0; i < names.size(); ++i)
{
// write the result
streamsize prec = cout.precision();
cout << names[i] << "'s final grade is " << setprecision(3)
<< final_grades[i]
<< setprecision(prec) << endl;
}
return 0;
}
3.6
#include <iomanip>
#ifndef __GNUC__
#include <ios>
#endif
#include <iostream>
#include <string>
using namespace std;
int main()
{
// ask for and read the student's name
cout << "Please enter your first name: ";
string name;
cin >> name;
cout << "Hello, " << name << "!" << endl;
// ask for and read the midterm and final grades
cout << "Please enter your midterm and final exam grades: ";
double midterm, final;
cin >> midterm >> final;
// ask for the homework grades
cout << "Enter all your homework grades, "
"followed by end-of-file: ";
// the number and sum of grades read so far
int count = 0;
double sum = 0;
// a variable into which to read
double x;
// invariant:
// we have read `count' grades so far, and
// `sum' is the sum of the first `count' grades
while (cin >> x)
{
++count;
sum += x;
}
double homework_grade = (count > 0) ? sum / count : 0.0;
// write the result
streamsize prec = cout.precision();
cout << "Your final grade is " << setprecision(3)
<< 0.2 * midterm + 0.4 * final + 0.4 * homework_grade
<< setprecision(prec) << endl;
return 0;
}
Accelerated C++ 学习笔记及题解----第三章
标签：des style blog http io os ar for 2014
原文地址：http://blog.csdn.net/suool/article/details/39276507
