实验7流类库和输入输出

#include<iostream>
using namespace std;
int main() {
    ios_base::fmtflags original_flags = cout.flags();//保存现在的格式化参数的设置
    cout << 812 << ‘|‘;
    cout.setf(ios_base::left, ios_base::adjustfield);//左对齐值
    cout.width(10);//设置输出宽度为10
    cout << 813 << 815 << ‘\n‘;
    cout.unsetf(ios_base::adjustfield);//取消之前调用setf()的效果
    cout.precision(2);
    cout.setf(ios_base::uppercase | ios_base::scientific);//使用科学技术法输出，且对于16进制输出时，使用大写字母，E表示。
    cout << 831.0;
    cout.flags(original_flags);//恢复初始参数
    return 0;
}

#include<iostream>
#include<fstream>
#include<string>
using namespace std;
int main(){
    ofstream os("test1.txt");
    if (os) {
        os << "已成功写入文件！";
    }
    os.close();
    ifstream is("test1.txt");
    if (is) {
        string s1;
        getline(is, s1);
        cout << s1;
    }
    is.close();
    return 0;
}

#include<iostream>
#include<fstream>
#include<string>
#include<cstdlib>
#include<ctime>
using namespace std;
struct stu {
    int num;
    string num2, name, room;
}student[100];
int main() {
    ifstream is("list.txt");
    if (!is) {
        cout << "ERROR" << endl;
        return 1;
    }
    int i = 0;
    while (is >> student[i].num >> student[i].num2 >> student[i].name >> student[i].room) {
        i++;
    }
    is.close();
    ofstream os("roll.txt");
    srand((unsigned)time(NULL));
    for (int i = 0; i < 5; i++) {
        int m = (rand() % 83);
        cout << student[m].num << " " << student[m].num2 << " " << student[m].name << " " << student[m].room << endl;
        os << student[m].num << " " << student[m].num2 << " " << student[m].name << " " << student[m].room << endl;
    }
    os.close();
    return 0;
}

#include<iostream>
#include<fstream>
#include<string>
using namespace std;
int main() {
    ifstream is("article.txt");
    int line = 0; int num1 = 0; int word = 0;
    if (is) {
        string s1; int m;
        while (getline(is, s1)) {
            m = s1.size();
            line++;
            num1 = num1 + m;
            for (int i = 0; i < m; i++) {
                if (s1[i] >= ‘A‘&&s1[i] <= ‘Z‘ || s1[i] >= ‘a‘&&s1[i] <= ‘z‘) {
                    if (s1[i + 1] >= ‘!‘&&s1[i + 1] <= ‘/‘||s1[i+1]==‘ ‘||s1[i+1]>=‘:‘&&s1[i+1]<=‘?‘) {
                        word++;
                    }
                }
            }
        }
    }
    is.close();
    cout <<"行数为："<< line << " 字符数为：" << num1 <<" 单词数为："<<word<< endl;
    return 0;
}