Reading of integers from file

Asked Jun 06 '15 at 15:50

Active Jun 06 '15 at 15:54

Viewed 67 times

I have to read integers from file, that are written for example so: The first number shows the number of the lines.

This should be the result: [2:44][11:3][44:3][2:11]

This is my code:

int read() {
    std::ifstream file("file.dat");
    int s;
    int p;

    if (!file) {
        std::cout<<"File cant´t be open"<<std::endl;
        return 0;
    }else {
    while(file>>s && file>>p) {

        std::cout<<"["<<s<<":"<<p<<"]";
    }
    /*  for(int i=0; i<count; i++) { 
            std::cout<<"["s[i]<<":"<<p[i]<<"]";
*/

file.close(); 
}
return 0;

}

But the result is: [4:2][44:11][3:44][3:2]

How can I define,that the first number shows the lines,where the two numbers stay?

edited Jun 06 '15 at 15:54

Baum mit Augen

49,044
25
144
182

asked Jun 06 '15 at 15:50

Diana Papukchieva

3

Why don't you just read the single integer before you start your loop? Or is the number of non whitespace lines you need to skip not known before? – Baum mit Augen Jun 06 '15 at 15:52
1

You forget the first single integer – Razib Jun 06 '15 at 15:55
I tried so: else { int beginning; file>>beginning; while(file>>s && file>>p) { for(int i=0; i – Diana Papukchieva Jun 06 '15 at 15:56
@DianaPapukchieva Of course they are, you told the compiler that you want that with your `for`-loop. Get rid of that and it will print only once. – Baum mit Augen Jun 06 '15 at 15:57
Oh,yes,i get it }else { int beginning; file>>beginning; while(i>s; file>>p; std::cout<<"["< – Diana Papukchieva Jun 06 '15 at 16:07
You should search StackOverflow for "c++ read from file structure". It's all about parsing the separators. – Thomas Matthews Jun 06 '15 at 18:46
Possible duplicate: https://stackoverflow.com/questions/8116808/read-integers-from-a-text-file-with-c-ifstream – Jerry Jeremiah Jan 30 '20 at 21:58

Reading of integers from file

0 Answers0