实验7

11-7
#include 
using namespace ::std;
int main() {
ios_base::fmtflags original_flags = cout.flags(); //保存cout格式化参数设置 
cout<< 812<<'|';
cout.setf(ios_base::left,ios_base::adjustfield); //输出对齐方式为左对齐 
cout.width(10); //输出宽度为10 
cout<< 813 << 815 << '/n';
cout.unsetf(ios_base::adjustfield); //取消输出对齐 
cout.precision(2); 
cout.setf(ios_base::uppercase|ios_base::scientific); //科学计数法显示浮点数 
cout << 831.0 ;
cout.flags(original_flags); //恢复原参数
return 0;
}

11-3

#include
#include
using namespace std;
int main()
{   
    ofstream out("text.txt");
    out<<"已成功写入文件！";
    out.close(); 
     return 0;
 } 

11-4

#include
#include
using namespace std;
int main()
{   
    ifstream put("text.txt");
string t;
getline(put,t);
cout<<t;
put.close();
return 0; 
 } 

2-1

#include
#include
#include
#include
#include
using namespace std;
struct student
{
    string xh,name,cl;
    int num;
 } xs[100];
 int main()
 {
     ifstream fin("liss.txt");
     ofstream fout("roll.txt");
     int i=0;
     while(fin>>xs[i].num>>xs[i].xh>>xs[i].name>>xs[i].cl)
     i++;
     fin.close();
     int line=i;
     srand(time(NULL));
     for(i=0;i<5;i++)
     {
         int a=rand()%line+1;
         cout<" "<" "<" "<endl;
         fout<" "<" "<" "<endl;
     }
     fout.close();
     return 0;
}

2-2

#include
#include
#include
using namespace std;
int main()
{
    ifstream out("ss.txt");
    int words=0,lines=0,num=0;
    string w;
    while(getline(out,w)){
         const char *p=w.c_str();
         for(int i=0;i)
         {
            if(p[i]==' ') words++;
         }
         words++;
         lines++;
         num+=w.size();
    }
    cout<<"单词数："<" "<<"行数："<" "<<"字符数："<endl;
    out.close();
    return 0;
}