第七次实验

//11-7 
#include<iostream>
using namespace std;
int main()
{
    ios_base::fmtflags original_flags=cout.flags();
//    flag指针?指向开头? 
    cout<<812<<'|';
    cout.setf(ios_base::left,ios_base::adjustfield);
//  输出左对齐 
    cout.width(10);
//  输出长度位10 
    cout<<813<<815<<'\n';
    cout.unsetf(ios_base::adjustfield);
//  调整,取消左对齐 
    cout.precision(2);
    cout.setf(ios_base::uppercase|ios_base::scientific);
//  科学计数法表示,并且小数点后保留两位有效数字 
    cout<<831.0;
    cout.flags(original_flags);    
    return 0;
}

//11-8 
#include<fstream>
#include<iostream>
#include<string>
using namespace std;
int main()
{
    ofstream fout("text1.txt");
    if(!fout){
        cout << "fail to build" << endl;
        return 0;
    }
    fout << "已成功写入文件!";
    fout.close();
    return 0;
}

//11-9 
#include<iostream>
#include<fstream>
using namespace std;
int main()
{
    string s;
    ifstream fin("text1.txt");
    if(!fin){
        cout << "fail to open" << endl;
        return 0;
    }
    fin >> s;
    cout << s <<endl;
    fin.close();
    return 0;
} 

//应用练习1
#include<iostream> #include<fstream> #include<vector> #include<ctime> #include<string> using namespace std; struct stu { string i1; string i2; string i3; string i4; }; int main() { ifstream fin("list.txt"); stu k; vector<stu> tar; if(!fin){ cout << "fail to open"<<endl; return 0; } string i1,i2,i3,i4; while(fin >> i1 >> i2 >> i3 >> i4){ k.i1=i1,k.i2=i2,k.i3=i3,k.i4=i4; tar.push_back(k); } fin.close(); vector<stu> d; srand((unsigned)time(NULL)); while(d.size()<5){ d.push_back(tar[rand()%83]); } ofstream fout("roll.txt"); for(int i=0;i<d.size();i++){ fout << d[i].i1 << " " << d[i].i2 << " "; fout << d[i].i3 << " " << d[i].i4 << endl; } fout.close(); return 0; }

//应用练习2
#include<iostream> #include<string> #include<fstream> using namespace std; int main() { ifstream fin1("num1.txt"); char ch,prech='\n'; int line=0,word=0,words=0; while((ch=fin1.get())!=EOF){ if(ch=='\n')line++; if(ch!=' '&&ch!='\n')word++; if((prech==' '&&ch!=' ')||(prech=='\n'&&ch!=' '))words++; prech=ch; } cout << "num.txt has "<< word << " word" << endl; cout << "num.txt has "<< words << " words" << endl; cout << "num.txt has "<< line << " line" << endl; return 0; }

posted @ 2018-06-20 21:25 tacore 阅读(...) 评论(...) 编辑 收藏