fscanf() - I/O Function

Tutorials

Cpp

Topic

How is "fscanf()" used in C++?

Explanation

fscanf() is an I/O function similar to scanf but this function reads information from a stream. The function returns the number of items read on success, it can be zero if a matching failure occurs. If an input failure occurs before reading data could result in EOF.

Syntax:

    int fscanf( FILE * stream, const char *format,...);

In the above syntax in the format parameter the function discards the whitespace.All the non-whitespace characters except "%" are skipped, then the next character is read. The "%" indicates a format specifier. The following table lists the format specifier used with "fscanf" function.

Type	Description	Argument
c	Used to read a single character, if the width is more than 1 the function reads all the specified width of characters and stores them in successive locations of the array passed as argument.	char *
d	Represents a decimal integer that mey be preceeded with +/ - sign.	int *
e,E,f,g,G	Used to represent a floating point number containing a decimal point that may have a +/- sign with a e or E character.	float *
o	Specifies an octal value	int *
s	This format type is used to read string of characters until a whitespace is found.	char *
u	Unsigned decimal integer	unsigned int *
x,X	Represents a hexadecimal integer.	int *

Example:

   #include <stdio.h>
   int main() 
     {
       FILE *fp;
       char name[100];
       fp = fopen("fscanfeg.txt", "r");
       fscanf(fp, "%s", name);
       printf("%s\n", name);
       fclose(fp);
       return 0;
     }

Result:

    Hscripts

In the above example the "fscanf()" is used to read the text "Hscripts" from the text file.