National Instruments 320682C

Chapter 2 Formatting and I/O Library

Integer and Real to String with Literals

char buf[20];

int f, r;

double v;

f = 4;

r = 3;

v = 1.2;

Fmt (buf, "%s<F%iR%i; V%f;", f, r, v);

Remarks

After the Fmt call, buf contains "F4R3; V1.2;".

Two Integers to ASCII File with Error Checking

int a, b, n, file_handle;

a = 12;

b = 456;

file_handle = OpenFile ("FILE.DAT", 2, 0, 1);

if (file_handle < 0) {

FmtOut ("Error opening file\n");

exit (1);

}

n = FmtFile (file_handle, "%s<%i %i", a, b);

if (n != 2) {

FmtOut ("Error writing file\n");

exit (1);

}

CloseFile (file_handle);

Remarks

OpenFile opens the file FILE.DAT as an ASCII file for writing only. If the function

succeeds, it returns a file handle with a positive integer value. FmtFile writes the ASCII

representation of two integer values to the file. If FmtFile succeeds, it returns 2 (because there

are two source specifiers in the format string).

Real Array to ASCII File in Columns and with Comma Separators

double x[100];

int file_handle, i;

file_handle = OpenFile ("FILE.DAT", 2, 0, 1);

for (i=0; i < 100; i++) {

FmtFile (file_handle, "%s<%f[w15],", x[i]);