实验7

实验7

基础练习

注释

11-7

#include <iostream>
using namespace ::std;
int main() {
ios_base::fmtflags original_flags = cout.flags(); //保存cout参数设置 
cout<< 812<<'|';
cout.setf(ios_base::left,ios_base::adjustfield); //设置cout的对齐方式为左对齐 
cout.width(10); //将cout宽度改为10 
cout<< 813 << 815 << '/n';
cout.unsetf(ios_base::adjustfield); //取消cout对齐方式的设置 
cout.precision(2);// 设置浮点数输出的精度值 
cout.setf(ios_base::uppercase|ios_base::scientific); //设置浮点数的显示参数 
cout << 831.0 ;
cout.flags(original_flags); //恢复cout原参数设置 
return 0;
}

运行结果

应用

源码：

#include<iostream>
#include<string>
#include<fstream>
#include<vector>
#include<ctime>
#include<cstdlib>
using namespace std;
class student{
	public:
		int num;
		string name;
		long long id;
		string group;
};
int main(){
	ifstream fin("list.txt");
	student temp;
	vector<student> stu;
	while(fin>>temp.num>>temp.id>>temp.name>>temp.group){
		stu.push_back(temp); 
	}
	ofstream fout("roll.text",ios::out);
	srand((unsigned)time(NULL));
	for(int i=0;i<5;i++){
		int t=rand()%(stu.size());
		cout<<stu[t].num<<" "<<stu[t].id<<" "<<stu[t].name<<" "<<stu[t].group<<endl;
		fout<<stu[t].num<<" "<<stu[t].id<<" "<<stu[t].name<<" "<<stu[t].group<<endl;
	}
	return 0;
}