11-7 #include<iostream> using namespace std; int main() { ios_base::fmtflags original_flags=cout.flags();//保存初始化参数 cout<<812<<"|"; cout.setf(ios_base::left,ios_base::adjustfield);//对齐方式为左对齐 cout.width(10);//指定输出宽度为10 cout<<813<<815<<"\n"; cout.unsetf(ios_base::adjustfield);//清除对齐方式 cout.precision(2); cout.setf(ios_base::uppercase|ios_base::scientific);//改变数字结果显示方式 cout<<831.0; cout.flags(original_flags);//恢复初始化参数 return 0; }
11-3、11-4 #include<iostream> #include<fstream> using namespace std; int main() { ofstream file; file.open("text1"); file<<"已成功写入文件!"<<endl; file.close(); return 0; }
#include<iostream> #include<fstream> #include<cstring> using namespace std; int main() { ifstream in; string file_name; while(cin >> file_name){ in.open(file_name.c_str(), ios::in); if(!in){ cout<<"fail to open"<<endl; return 1; } int words=0,lines=0,nums=0; string w; while(getline(in,w)){ nums+=w.size(); for (int i = 0; i < w.size() ; i++) { if (w[i]==' ')words++; } words++; lines++; } cout<<"单词数:"<<words<<" "<<"行数:"<<lines<<" "<<"字符数:"<<nums<<endl; in.close();} return 0; }
#include<iostream> #include<cstring> #include<fstream> #include<cstdlib> #include<ctime> using namespace std; struct student { string num; string id,name,cls; }stu[10000]; int main() { ifstream fin("list1.txt"); ofstream fout("roll.txt"); int i; while(fin>>stu[i].num>>stu[i].id>>stu[i].name>>stu[i].cls) { i++; } fin.close(); int line=i; int a; srand(time(NULL)); for(int i=0;i<5;i++) { a=rand()%(line-1+1)+1; cout<<stu[a].num<<" "<<stu[a].id<<" "<<stu[a].name<<" "<<stu[a].cls<<endl; fout<<stu[a].num<<" "<<stu[a].id<<" "<<stu[a].name<<" "<<stu[a].cls<<endl; } fout.close(); return 0; }
对我来说实验难度较大,难以独自完成,还需要多看多练。