Usage of C ++ fstream and getline

Example: data.txt File Content

1. Easy to burn

2 light, no pain, normal light

 

Use the C ++ fstream and Getline methods to read information into a two-dimensional array string data [] []

 

Method 1: (applicable to known rows and columns, separated by spaces or tabs)

# Include <fstream>

# Include <string>

Using namespace STD;

Void main ()

{

Ifstream ifile ("data.txt ");

String data [2] [6];

For (INT I = 0; I <2; I ++)

For (Int J = 0; j <6; j ++)

Ifile> data [I] [J];

Ifile. Close ();

}

 

Method 2: (the number of unknown rows and columns are separated by spaces)

# Include <fstream>

# Include <string>

# Include <vector>

Using namespace STD;

Typedef vector <string> VVS;

Void main ()

{

Ifstream infile ("data.txt ");

Infile> noskipws; // do not ignore the blank and read the '/N' at the end of each line.

 

// Determine the number of rows and columns. Data in each column in the file is separated by spaces.

Int row, Col, K;

Row = Col = 0;

Char CHR;

While (infile> CHR)

{

Switch (CHR)

{

Case '/N': // determines whether the character to be read is a line break

+ + Row; // if it is a line break, the number of rows + 1

Col = 0; // if it is a line break, the number of columns is cleared.

Break;

Case '': // determines whether the characters to be read are blank.

+ + Col; // The number of columns + 1

Break;

Default :;

}

}

Infile. Close (); // close a text file

Row ++; Col ++; // The number of rows and columns obtained by reading the file plus 1 is the actual number of rows and columns (Note: there are no blank lines at the end of the file)

 

Vvs data; // defines a two-dimensional string array.

Data. resize (row );

For (k = 0; k <row; k ++)

Data [k]. resize (col );

 

Ifstream infile2 ("data.txt ");

Int trow, tcol;

Trow = tcol = 0;

String str;

While (trow <row) // loop comparison, with the number of rows as the limit

{

While (tcol <col-1)

{

Getline (infile2, str, ''); // separate objects with spaces for Data Reading

Data [trow] [tcol] = str; // Save the data before the space to the corresponding string array.

Tcol ++; // The number of Columns after data is saved + 1

}

Getline (infile2, str, '/N'); // enter the carriage return as an object to determine whether a row ends.

Data [trow] [tcol] = str; // read the data before the carriage return to the corresponding string array.

Tcol = 0; // The number of columns is assigned to 1 to determine the next row.

Trow ++; // number of rows + 1

}

Infile2.close ();

}