Read Input From a File Using Scanf

C library function - fscanf()

---

Clarification

The C library role int fscanf(FILE *stream, const char *format, ...) reads formatted input from a stream.

Annunciation

Following is the declaration for fscanf() function.

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

Parameters

• stream − This is the pointer to a FILE object that identifies the stream.

• format − This is the C string that contains i or more of the post-obit items − Whitespace character, Not-whitespace character and Format specifiers. A format specifier will be every bit [=%[*][width][modifiers]type=], which is explained below −

Sr.No.	Statement & Description
1	* This is an optional starting asterisk indicates that the data is to be read from the stream simply ignored, i.east. it is not stored in the corresponding argument.
2	width This specifies the maximum number of characters to exist read in the electric current reading operation.
iii	modifiers Specifies a size dissimilar from int (in the case of d, i and n), unsigned int (in the case of o, u and 10) or float (in the instance of e, f and one thousand) for the information pointed past the respective additional statement: h : curt int (for d, i and n), or unsigned short int (for o, u and ten) 50 : long int (for d, i and n), or unsigned long int (for o, u and ten), or double (for e, f and k) Fifty : long double (for due east, f and g)
4	type A graphic symbol specifying the type of data to be read and how it is expected to be read. Come across next table.

fscanf type specifiers

type	Qualifying Input	Blazon of argument
c	Unmarried grapheme: Reads the next character. If a width different from i is specified, the office reads width characters and stores them in the successive locations of the array passed as statement. No aught character is appended at the end.	char *
d	Decimal integer: Number optionally preceded with a + or - sign	int *
due east, E, f, g, G	Floating bespeak: Decimal number containing a decimal signal, optionally preceded by a + or - sign and optionally followed by the e or E character and a decimal number. Ii examples of valid entries are -732.103 and 7.12e4	float *
o	Octal Integer:	int *
due south	String of characters. This will read subsequent characters until a whitespace is found (whitespace characters are considered to be blank, newline and tab).	char *
u	Unsigned decimal integer.	unsigned int *
x, 10	Hexadecimal Integer	int *

• additional arguments − Depending on the format string, the role may expect a sequence of additional arguments, each containing 1 value to exist inserted instead of each %-tag specified in the format parameter (if any). There should be the same number of these arguments as the number of %-tags that look a value.

Return Value

This function returns the number of input items successfully matched and assigned, which tin can be fewer than provided for, or fifty-fifty cipher in the event of an early matching failure.

Case

The following example shows the usage of fscanf() part.

#include <stdio.h> #include <stdlib.h>   int master () {    char str1[x], str2[10], str3[10];    int year;    FILE * fp;     fp = fopen ("file.txt", "due west+");    fputs("We are in 2012", fp);        rewind(fp);    fscanf(fp, "%due south %s %southward %d", str1, str2, str3, &year);        printf("Read String1 |%south|\due north", str1 );    printf("Read String2 |%s|\n", str2 );    printf("Read String3 |%s|\north", str3 );    printf("Read Integer |%d|\north", year );     fclose(fp);        render(0); }        

Let usa compile and run the higher up program that will produce the following result −

Read String1 |We| Read String2 |are| Read String3 |in| Read Integer |2012|        

stdio_h.htm

Useful Video Courses

---

Video

Video

Video

Video

Video

Video

mcclainthioseen37.blogspot.com

Source: https://www.tutorialspoint.com/c_standard_library/c_function_fscanf.htm

Share this post