How to read numercial data from a file

[Wei-Chao Hsu]

There are some data files look like

1.) data1.txt
----------------
1.0 2.0 3.0
4.0 5.0 6.0
7.0 8.0 9.0
10.0

2.) data2.txt
---------------------
1.0 2.0 3.0 4.0
5.0 6.0 7.0 8.0
9.0 10.0

3.) data3.txt
----------------
1.0 2.0
3.0 4.0 5.0
6.0 7.0
8.0 9.0 10.0

They will be store in a array. A[0]=1.0,A[1]=2.0,.....
I never know the format in each file.
In fortran, I just declare an array A(10), and read them
READ(file_no,*)A
I don't know how to do the same thing in C.
I need your help. Thanks!

Dennis

 

[John Harrison]

There are some data files look like

1.) data1.txt
----------------
1.0 2.0 3.0
4.0 5.0 6.0
7.0 8.0 9.0
10.0

2.) data2.txt
---------------------
1.0 2.0 3.0 4.0
5.0 6.0 7.0 8.0
9.0 10.0

3.) data3.txt
----------------
1.0 2.0
3.0 4.0 5.0
6.0 7.0
8.0 9.0 10.0

They will be store in a array. A[0]=1.0,A[1]=2.0,.....
I never know the format in each file.
In fortran, I just declare an array A(10), and read them
READ(file_no,*)A
I don't know how to do the same thing in C.
I need your help. Thanks!

Dennis

Well its not so difficult in C++ (I assume you mean C++ not C, since you
posted to a C++ group), You just declare the array and read them. The only
difference is that you must read in some sort of loop.

#include <fstream>

std::ifstream file("data1.txt");
double a[10];
for (int i = 0; i < 10; ++i)
file >> a;

If you want a C answer post to
john

 

[Thomas Matthews]

There are some data files look like

1.) data1.txt
----------------
1.0 2.0 3.0
4.0 5.0 6.0
7.0 8.0 9.0
10.0

[snip]

Dennis

Well its not so difficult in C++ (I assume you mean C++ not C, since
you posted to a C++ group), You just declare the array and read them.
The only difference is that you must read in some sort of loop.

#include <fstream>

std::ifstream file("data1.txt");
double a[10];
for (int i = 0; i < 10; ++i)
file >> a;

If you want a C answer post to
john

Actually, he did. Perhaps, I didn't pay attention
to the time and date stamps of these posts. ;-)


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