实验7
一:
#include<iostream> using namespace std; int main() { ios_base::fmtflags original_flags=cout.flags(); cout<<812<<'|'; cout.setf(ios_base::left,ios_base::adjustfield); //将格式调整为左对齐 cout.width(10); //设置宽度为10 cout<<813<<815<<'\n'; cout.unsetf(ios_base::adjustfield); //取消已设的格式定义 cout.precision(2); //设置精度为2 cout.setf(ios_base::uppercase|ios_base::scientific);//用科学格式显示浮点数值 ,对于科学数值显示大写字母E cout<<813.0; cout.flags(original_flags); // 回复初始 return 0; }
二:
#include<iostream> #include<fstream> using namespace std; int main() { ofstream out("test1.txt"); if(!out){ cout<<"文件未能打开。"<<endl; return 1; } out<<"已成功写入文件!"<<endl; out.close(); return 0; }
三:
#include<iostream> #include<fstream> #include<string> using namespace std; int mian() { ifstream in("test1.txt"); if(!in){ cout<<"文件未能打开。"<<endl; return 1; } char ch; while(ch=in.get()!=EOF) cout.put(ch); in.close(); return 0; }
四:
#include<iostream> #include<fstream> #include<cstdlib> #include<string> #include<ctime> using namespace std; struct student{ int number; string id,name,cl; }student[83]; int main() { ifstream in("list.txt"); if(!in){ cout<<"Error"<<endl; return 1; } for(int i=0;i<83;i++){ in>>student[i].number>>student[i].id>>student[i].name>>student[i].cl; } in.close(); ofstream out("roll.txt"); for(int i=0;i<5;i++){ int a; a=rand()%83+1; out<<student[a].number<<" "<<student[a].id<<" "<<student[a].name<<" "<<student[a].cl<<endl; } return 0; }