#include <iostream>
#include <iomanip>
#include <string>
#include <bitset>
using namespace std;
int main () {
int x;
cin >> oct >> x;
cout << dec << x << endl;
cout << setw(20) << setfill('*') << "I am a student!" << endl;
double pi = 3.1415926;
cout << setprecision(8) << pi << endl;
cout << setprecision(6) << pi << endl;
cout << setprecision(4) << pi << endl;
bitset<64> bin(*((unsigned long long*)&pi));
cout << bin << endl;
}
#include <iostream>
#include <iomanip>
#include <string>
#include <bitset>
using namespace std;
int main () {
int x;
cin >> oct >> x;
cout << dec << x << endl;
cout.width(20);
cout.fill('*');
cout.flags(ios::left);
cout << "I am a student!" << endl;
double pi = 3.1415926;
cout.precision(8);
cout.flags(ios::fixed);
cout << pi << endl;
cout.precision(6);
cout.flags(ios::fixed);
cout << pi << endl;
cout.precision(4);
cout.flags(ios::fixed);
cout << pi << endl;
bitset<64> bin(*((unsigned long long*)&pi));
cout << bin << endl;
}
#include <iostream>
#include <string>
using namespace std;
int main()
{
char str1[20], str2[20], str3[20];
cin.get(str1, 20, '/');
cout << str1 << endl;
cin.get(str2, 20, '/');
cout << str2 << endl;
cin.get(str3, 20, '/');
cout << str3 << endl;
return 0;
}
#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
int main()
{
ofstream outfile("Prime.txt");
if (!outfile)
{
cerr << "error: unable to open output file: "
<< "Prime.txt" << endl;
return -1;
}
outfile << 2 << endl;
for (int i = 3; i < 1000; i += 2)
{
bool isPrime = true;
for (int j = 3; j <= sqrt(i); j += 2)
{
if (i % j == 0)
{
isPrime = false;
break;
}
}
if (isPrime)
outfile << i << endl;
}
outfile.close();
return 0;
}
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main()
{
string filename;
cout << "Please input the filename: ";
cin >> filename;
ifstream infile(filename);
if (!infile)
{
cout << "Error opening " << filename << endl;
return -1;
}
int n;
infile >> n;
double x, y, z;
for (int i = 0; i < n; i++)
{
infile >> x >> y >> z;
cout << x << " " << y << " " << z << endl;
}
infile.close();
return 0;
}
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
struct Teacher {
int id;
string name;
char gender;
};
int main () {
ofstream outfile("teacher.dat", ios::binary);
int N;
cin >> N;
for (int i = 0; i < N; i++) {
Teacher t;
cin >> t.id >> t.gender >> t.name;
outfile << i + 1 << " " << t.id << t.name << t.gender << endl;
}
outfile.close();
}
#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
int main()
{
ifstream in("f1.txt", ios::in | ios::binary);
ofstream out("f2.txt", ios::out | ios::binary);
if (!in || !out)
{
cout << "Error opening file!" << endl;
return 0;
}
int a[100];
int i = 0;
while (in.read((char *)&a[i], sizeof(int)))
{
i++;
}
sort(a, a + i);
for (int j = 0; j < i; j++)
{
out.write((char *)&a[j], sizeof(int));
cout << a[j] << " ";
}
cout << endl;
in.close();
out.close();
return 0;
}
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
ofstream outfile("M99.txt");
if (!outfile)
{
cerr << "open error!" << endl;
abort();
}
for (int i = 1; i <= 9; i++)
{
for (int j = 1; j <= i; j++)
outfile << j << "*" << i << "=" << i * j << "\t";
outfile << endl;
}
outfile.close();
return 0;
}
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <algorithm>
#include <cctype>
using namespace std;
int main()
{
ifstream in("hello.cpp");
if (!in)
{
cerr << "open file error!" << endl;
return -1;
}
string line;
vector<string> words;
while (getline(in, line))
{
string::size_type beg = 0, end;
while (beg != line.size())
{
while (beg != line.size() && isspace(line[beg]))
++beg;
end = beg;
while (end != line.size() && !isspace(line[end]))
++end;
if (beg != end)
words.push_back(line.substr(beg, end - beg));
beg = end;
}
}
cout << "words: " << words.size() << endl;
sort(words.begin(), words.end());
vector<string>::iterator end_unique = unique(words.begin(), words.end());
words.erase(end_unique, words.end());
cout << "unique words: " << words.size() << endl;
return 0;
}
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
ofstream outfile("testl.txt");
if (!outfile)
{
cerr << "open error!" << endl;
abort();
}
outfile << "已成功写人文件!" << endl;
outfile.close();
return 0;
}
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main()
{
ifstream infile("test1.txt");
if (!infile)
{
cout << "open error!" << endl;
return 1;
}
string s;
while (getline(infile, s))
{
cout << s << endl;
}
}
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main()
{
ofstream outfile("testl.txt", ios::app);
if (!outfile)
{
cerr << "open error!" << endl;
abort();
}
outfile << "已成功添加字符!" << endl;
outfile.close();
ifstream infile("testl.txt");
if (!infile)
{
cerr << "open error!" << endl;
abort();
}
string str;
while (getline(infile, str))
{
cout << str << endl;
}
infile.close();
return 0;
}
#include <iostream>
#include <fstream>
using namespace std;
class Dog
{
private:
int weight;
int age;
public:
Dog(int w, int a):weight(w), age(a){}
void show()
{
cout << "weight: " << weight << " age: " << age << endl;
}
void save(ofstream &out)
{
out.write((char*)&weight, sizeof(weight));
out.write((char*)&age, sizeof(age));
}
void load(ifstream &in)
{
in.read((char*)&weight, sizeof(weight));
in.read((char*)&age, sizeof(age));
}
};
int main()
{
Dog dog1(5, 10);
ofstream out("dog.dat", ios::binary);
dog1.save(out);
out.close();
Dog dog2(0, 0);
ifstream in("dog.dat", ios::binary);
dog2.load(in);
in.close();
dog2.show();
return 0;
}
#include <iostream>
using namespace std;
int main()
{
int a;
cout << "请输入一个十进制整数:";
cin >> a;
cout << "十进制:" << a << endl;
cout << "八进制:" << oct << a << endl;
cout << "十六进制:" << hex << a << endl;
return 0;
}
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main()
{
string s1, s2;
cin >> s1 >> s2;
ifstream infile(s1);
ofstream outfile(s2);
string s;
int i = 1;
while (getline(infile, s))
{
outfile << i << " " << s << endl;
i++;
}
infile.close();
outfile.close();
return 0;
}
#include <iostream>
#include <fstream>
#include <string>
#include <map>
using namespace std;
int main()
{
wifstream in("hello.txt");
wofstream out("result.txt");
map<wchar_t, int> m;
wchar_t c;
while (in >> c)
{
m[c]++;
}
for (map<wchar_t, int>::iterator iter = m.begin(); iter != m.end(); iter++)
{
out << iter->first << L" " << iter->second << endl;
}
return 0;
}
标签:std,cout,int,编程,namespace,面向对象,using,打卡,include
From: https://www.cnblogs.com/sugar-refinery/p/17413479.html