Description

The C library function, The fprintf( ) function used for write data to text file.

Declaration

Following is the declaration for fprintf() function.

int fprintf(FILE *stream, const char *format,[argu1,argu2 .... argun  ]);

Parameters

Stream - This is the Pointer to a FILE object that identifies an output stream.

Format - Here control string refers to a string that contains formatting information, and arg1,are argument that represent the individual output data items. The argument may include variables, constants and stringgs. It can optionally contain embedded format specifiers that are replaced by the values specified in subsequent additional arguments and formatted as requested.

A format specifier follows this prototype:

%[flags][width][.precision][length]specifier

Where the specifier character at the end is the most significant component, since it defines the type and the interpretation of its corresponding argument:

The format specifier can also contain sub-specifiers: flags, width, .precision and modifiers (in that order), which are optional and follow these specifications:

additional arguments - Depending on the format string, The control string can include a flag, Which affects the appearance of the output. The flag must be placed immediately after percent sign(%).There should be the same number of these arguments as the number of %-tags that expect a value.

Return Value

On success, the total number of characters written is returned otherwise, If an error occurs, it will return a negative value.

Example

#include <stdio.h>
#include <stdlib.h>

int main()
{
   FILE * fp;

   fp = fopen ("myfile.txt", "w+");
   fprintf(fp, "%s %s %s %d", "i", "am", "sandeep");
   
   fclose(fp);
   
   return(0);
}

Output

i am sandeep