In C, **`sscanf()`** is used to read formatted data. It works much like [scanf()](https://www.educative.io/answers/how-to-read-data-using-scanf-in-c) but the data will be read from a *string* instead of the console.

# How do we use this function?

In order to read formatted data from a string, first, we must know the syntax of the function, which is shown below. 

## Syntax

#include<stdio.h>

int main() {
    int sscanf(const char *read, const char *format,. . ., 
                storage_variables )
}

Now let's look at what parameters does this function take and what it returns.

## Parameters

* **`read`:** This is the pointer to the string that is to be read.

* **`storage_variables`** Additional argument(s) that the function can take in order to store the value that is being read from the pointer. Here, if the value is being stored in a regular variable and not a pointer then the variable name must be preceded by the **&** sign.

* **`format`:** These are the **format specifiers** according to which the data will be read from the input string.

## Format Specifiers

A **format specifier** is a unique set of characters which is used to format the data being read in a certain way. It is preceded by a *%* sign and then the relevant symbol. The symbols are as follows: 

| Symbol        | Type           | 
| ------------- |:-------------:| 
| s     | string |
| c | single character    |
| d     |   decimal integer |
| e, E, f, g, G | floating points| 
| u | unsigned integer|
| x, X | hexadecimal number|

## Return Value

1. The function returns an `int` value which represents the total number of items read. 
2. Given there was an error and the string could not be read, an `EOF` error is returned. 
3. Any other type of error which is encountered while reading is denoted by the function returning *-1*.


Now that we know about the syntax, let's look at a few examples to better understand `sscanf()`.

# Examples

## 1. Reading one item of the same type

The first example shows you how to read just a single data type in an input string.

#include<stdio.h>

int main() {
    char* buffer = "Hello";
    char store_value[10];
    int total_read;

    total_read = sscanf(buffer, "%s" , store_value);

    printf("Value in buffer: %s",store_value);
    printf("\nTotal items read: %d",total_read);

    return 0;
}

## 2. Reading multiple items of the same type

The example below shows how to read a space separated two words long string into two separate variables.

#include<stdio.h>

int main() {
    char* buffer = "Hello World";
    char store_hello[10], store_world[10];
    int total_read;

    total_read = sscanf(buffer, "%s %s" , store_hello, store_world);

    printf("Value in first variable: %s",store_hello);
    printf("\nValue in second variable:  %s",store_world);
    printf("\nTotal items read: %d",total_read);
    return 0;
}

## 3. Reading multiple items of different types

The example below shows how to read a string and an integer from the same `buffer` value.

#include<stdio.h>

int main() {
    char* buffer = "Hello 20";
    char store_string[10];
    int store_integer;
    int total_read;

    total_read = sscanf(buffer, "%s %d" , store_string, &store_integer);

    printf("String value in buffer: %s" ,store_string);
    printf(" \nInteger value in buffer: %d",store_integer);
    printf("\nTotal items read: %d",total_read);
    return 0;
}

How to read data using sscanf() in C

In C, sscanf() reads formatted data from a string, using format specifiers like %d and %s.

Symbol	Type
s	string
c	single character
d	decimal integer
e, E, f, g, G	floating points
u	unsigned integer
x, X	hexadecimal number