使用 streampos 在文件中导航？

Question

我需要在使用 ifstream 加载的文件中导航。准确地说，我需要保存我之前所在的位置，以便在阅读几行后能够 return 到这个确切的位置。我试过类似的东西：

ifstream baseINTING("base.txt");
streampos position1, position2, position3;

position1 = baseINTING.tellg();

后来我看了几行：

getline(baseINTING, buffer2);

并试图返回：

baseINTING.seekg(position1);

但它不起作用。有人可以帮我吗？我真的需要那个结局。

这是完整代码：

#include <iostream>
#include <fstream>
#include <string>
#include <direct.h>
#include <cstdlib>


using namespace std;



void anyNextOne(ifstream* newFile)
{
    ifstream baseINTING("base.txt");
    int j;

    string  buffer2;
    streampos position1;


    getline(baseINTING, buffer2);
    getline(baseINTING, buffer2);

    position1 = baseINTING.tellg();


    for(j=0; j<5; j++)
    {
        getline(baseINTING, buffer2);

        cout<<buffer2<<endl;
        cout<<position1<<endl;

        baseINTING.seekg(position1);

    }

}
int main()
{
    ifstream one("one.txt");
    anyNextOne(&one);


    return 0;
}

示例输出：

食材（4人份）

40

（4人份）

40

（4人份）

40

(...)

"base.txt"文件内容：

Easy Pizza Recipe 
Dough:
Ingredients (for 4 people)
•   1 cup of warm water 
•   3 1/2 cups of flour
•   2 tablespoons of olive oil
•   2 teaspoons of honey 
•   1 teaspoon of salt
•   1 teaspoon of yeast 
Method:
1. Put warm water into a bowl. Add salt and honey and mix with a spoon. Add yeast, mix and let it sit for about 10 minutes.
2. add flour and olive oil and start mixing. 
3. Let it sit for about another hour. 
4. Put on some tomato sauce.
5. Put on your pizza topping (some green peppers, mushrooms, ketchup, cheese, sausage, salt and pepper) 
6. Bake the pizza in you oven at 200 C for about 20 to 25 minutes.

Answer 1

#include <iostream>
#include <fstream>
#include <string>
#include <direct.h>
#include <cstdlib>


using namespace std;



void anyNextOne(ifstream* newFile)
{
    ifstream baseINTING("base.txt");
    int j;

    string  buffer2;
    streampos position1;


    getline(baseINTING, buffer2);
    getline(baseINTING, buffer2);

    position1 = baseINTING.tellg();


    for(j=0; j<5; j++)
    {
        getline(baseINTING, buffer2);

        cout<<buffer2<<endl;
        cout<<position1<<endl;

        baseINTING.seekg(position1);

    }

}
int main()
{
    ifstream one("one.txt");
    anyNextOne(&one);


    return 0;
}

使用 streampos 在文件中导航？

Navigation in the file using streampos?

c++

file

input

codeblocks

ifstream