实验7

11.3

#include<iostream>
#include<fstream>
using namespace std;
int main() {
    ofstream test("test1.txt");
    test<< "已成功写入文件！";
    test.close();
    return 0;
}

11.4

#include<fstream>
#include<iostream>
using namespace std;
int main(){
    char ch;
    ifstream test1("test.txt");
    while(test1.get(ch))
    cout<<ch;
    test1.close();
}

11.7

#include <iostream>
using namespace ::std;
int main()
{
ios_base::fmtflags original_flags = cout.flags();
cout<< 812<<'|';
cout.setf(ios_base::left,ios_base::adjustfield);
cout.width(10);
cout<<813<<815<<'\n';
cout.unsetf(ios_base::adjustfield);
cout.precision(2);
cout.setf(ios_base::uppercase|ios_base::scientific);
cout << 831.0 ;
cout.flags(original_flags); 
}