Question

如何将我的程序转换为使用新的c ++标准？我对<iostream.h>等有疑问。

main.cpp:3:22: fatal error: iostream.h: No such file or directory 
#include <iostream.h>
          ^
compilation terminated.

这是在线编辑器：

http://www.compileonline.com/compile_cpp11_online.php

#include <iostream.h>
#include <fstream.h>
#include <string.h>
#include <iomanip.h>
#include <conio.h>

class phoneBook{
    char name[20],phno[15];
    public:
    void getdata();
    void showdata();
    char *getname(){ return name; }
    char *getphno(){ return phno; }
    void update(char *nm,char *telno){
        strcpy(name,nm);
        strcpy(phno,telno);
    }
};

void phoneBook :: getdata(){
    cout<<"\nEnter Name : ";
    cin>>name;
    cout<<"Enter Phone No. : ";
    cin>>phno;
}

void phoneBook :: showdata(){
    cout<<"\n";
    cout<<setw(20)<<name;
    cout<<setw(15)<<phno;
}


void main(){
    phoneBook rec;
    fstream file;
    file.open("d:\\phone.dat", ios::ate | ios::in | ios::out | ios::binary);
    char ch,nm[20],telno[6];
    int choice,found=0;
    while(1){
        clrscr();
        cout<<"\n*****Phone Book*****\n";
        cout<<"1) Add New Record\n";
        cout<<"2) Display All Records\n";
        cout<<"3) Search Telephone No.\n";
        cout<<"4) Search Person Name\n";
        cout<<"5) Update Telephone No.\n";
        cout<<"6) Exit\n";
        cout<<"Choose your choice : ";
        cin>>choice;
        switch(choice){
            case 1 : //New Record
                 rec.getdata();
                 cin.get(ch);
                 file.write((char *) &rec, sizeof(rec));
                 break;

            case 2 : //Display All Records
                 file.seekg(0,ios::beg);
                 cout<<"\n\nRecords in Phone Book\n";
                 while(file){
                    file.read((char *) &rec, sizeof(rec));
                    if(!file.eof())
                        rec.showdata();
                 }
                 file.clear();
                 getch();
                 break;

            case 3 : //Search Tel. no. when person name is known.
                 cout<<"\n\nEnter Name : ";
                 cin>>nm;
                 file.seekg(0,ios::beg);
                 found=0;
                 while(file.read((char *) &rec, sizeof(rec)))
                 {
                    if(strcmp(nm,rec.getname())==0)
                    {
                        found=1;
                        rec.showdata();
                    }
                 }
                 file.clear();
                 if(found==0)
                    cout<<"\n\n---Record Not found---\n";
                 getch();
                 break;

            case 4 : //Search name on basis of tel. no
                 cout<<"\n\nEnter Telephone No : ";
                 cin>>telno;
                 file.seekg(0,ios::beg);
                 found=0;
                 while(file.read((char *) &rec, sizeof(rec)))
                 {
                    if(strcmp(telno,rec.getphno())==0)
                    {
                        found=1;
                        rec.showdata();
                    }
                 }
                 file.clear();
                 if(found==0)
                    cout<<"\n\n---Record Not found---\n";
                 getch();
                 break;

            case 5 : //Update Telephone No.
                 cout<<"\n\nEnter Name : ";
                 cin>>nm;
                 file.seekg(0,ios::beg);
                 found=0;
                 int cnt=0;
                 while(file.read((char *) &rec, sizeof(rec)))
                 {
                    cnt++;
                    if(strcmp(nm,rec.getname())==0)
                    {
                        found=1;
                        break;
                    }
                 }
                 file.clear();
                 if(found==0)
                    cout<<"\n\n---Record Not found---\n";
                 else
                 {
                    int location = (cnt-1) * sizeof(rec);
                    cin.get(ch);
                    if(file.eof())
                        file.clear();

                    cout<<"Enter New Telephone No : ";
                    cin>>telno;
                    file.seekp(location);
                    rec.update(nm,telno);
                    file.write((char *) &rec, sizeof(rec));
                    file.flush();
                 }
                 break;
            case 6 : gotoout;
        }
    }
out:
file.close();
}

Answer 1

我看到的列表：

使用<iostream>标题
几乎整个标准库都在名称空间std
使用std :: string
int main
<conio.h>
在许多地方遗失const
删除goto，C ++一直有析构函数

Answer 2

这样可以更新标题：

#include <iostream>
#include <fstream>
#include <cstring>
#include <iomanip>

using namespace std;

class phoneBook{
    char name[20],phno[15];
    public:
    void getdata();
    void showdata();
    char *getname(){ return name; }
    char *getphno(){ return phno; }
    void update(char *nm,char *telno){
        strcpy(name,nm);
        strcpy(phno,telno);
    }
};

void phoneBook :: getdata(){
    cout<<"\nEnter Name : ";
    cin>>name;
    cout<<"Enter Phone No. : ";
    cin>>phno;
}

void phoneBook :: showdata(){
    cout<<"\n";
    cout<<setw(20)<<name;
    cout<<setw(15)<<phno;
}


int main(){
    phoneBook rec;
    fstream file;
    file.open("d:\\phone.dat", ios::ate | ios::in | ios::out | ios::binary);
    char ch,nm[20],telno[6];
    int choice,found=0;
    while(1){
        system("clear");
        cout<<"\n*****Phone Book*****\n";
        cout<<"1) Add New Record\n";
        cout<<"2) Display All Records\n";
        cout<<"3) Search Telephone No.\n";
        cout<<"4) Search Person Name\n";
        cout<<"5) Update Telephone No.\n";
        cout<<"6) Exit\n";
        cout<<"Choose your choice : ";
        cin>>choice;
        switch(choice){
            case 1 : //New Record
            {     rec.getdata();
                 cin.get(ch);
                 file.write((char *) &rec, sizeof(rec));
                 break;
            }
            case 2 : //Display All Records
            {     file.seekg(0,ios::beg);
                 cout<<"\n\nRecords in Phone Book\n";
                 while(file){
                    file.read((char *) &rec, sizeof(rec));
                    if(!file.eof())
                        rec.showdata();
                 }
                 file.clear();
                 getchar();
                 break;
            }
            case 3 : //Search Tel. no. when person name is known.
            {     cout<<"\n\nEnter Name : ";
                 cin>>nm;
                 file.seekg(0,ios::beg);
                 found=0;
                 while(file.read((char *) &rec, sizeof(rec)))
                 {
                    if(strcmp(nm,rec.getname())==0)
                    {
                        found=1;
                        rec.showdata();
                    }
                 }
                 file.clear();
                 if(found==0)
                    cout<<"\n\n---Record Not found---\n";
                 getchar();
                 break;
            }
            case 4 : //Search name on basis of tel. no
            {     cout<<"\n\nEnter Telephone No : ";
                 cin>>telno;
                 file.seekg(0,ios::beg);
                 found=0;
                 while(file.read((char *) &rec, sizeof(rec)))
                 {
                    if(strcmp(telno,rec.getphno())==0)
                    {
                        found=1;
                        rec.showdata();
                    }
                 }
                 file.clear();
                 if(found==0)
                    cout<<"\n\n---Record Not found---\n";
                 getchar();
                 break;
            }
            case 5 : 
            {
                 //Update Telephone No.
                 cout<<"\n\nEnter Name : ";
                 cin>>nm;
                 file.seekg(0,ios::beg);
                 found=0;
                 int cnt=0;
                 while(file.read((char *) &rec, sizeof(rec)))
                 {
                    cnt++;
                    if(strcmp(nm,rec.getname())==0)
                    {
                        found=1;
                        break;
                    }
                 }
                 file.clear();
                 if(found==0)
                    cout<<"\n\n---Record Not found---\n";
                 else
                 {
                    int location = (cnt-1) * sizeof(rec);
                    cin.get(ch);
                    if(file.eof())
                        file.clear();

                    cout<<"Enter New Telephone No : ";
                    cin>>telno;
                    file.seekp(location);
                    rec.update(nm,telno);
                    file.write((char *) &rec, sizeof(rec));
                    file.flush();
                 }
            }     break;
            case 6 :
            {goto outLabel;}    break;
        }
    }
outLabel:
file.close();

return 0;
}

要记住的事情：

是C ++ ，如果您打算使用它，您也应该使用它
cout，cin和类似需要命名空间std
main通常应返回int
如果您打算使用C ++编程，请尝试使用C ++和而非C函数
您应该尽可能使用字符串而不是char数组（在上面的代码中自己动手）

另外：使用gotos进行编程是一种可怕的做法，也是美味意大利面条代码的配方：

enter image description here

Answer 3

试试这个

#include <iostream>

iostream.h已经过时了，已被iostream取代

如何将我的程序转换为使用新的c ++标准？ <iostream.h> etc </iostream.h>

3 个答案: