C scanf()

The scanf() function (short for ‘scan formatted’) reads user input, interprets it according to the specified format, and assigns the converted value to a variable.

Syntax

int scanf(const char *format, &variable1, &variable2, ..., &variableN);

• format: A string containing format specifiers (e.g., %d, %f, %s) that define the type of input expected.
• &variable1, &variable2, ..., &variableN: Pointers to variables where the values from the input will be stored. Each pointer corresponds to a format specifier in the format string.

For a short list of format specifiers you can use in the input string, see the ‘Format Specifiers’ table in the printf documentation.

Note: scanf() does not have any intrinsic validation of the user input. This can cause errors if the user input does not match the format specifiers in the string.

Example 1

In the following example, the format specifier %d tells the function to expect an integer, then assigns it to the variable yourNumber:

#include <stdio.h>

int main(void) {
  int yourNumber;

  printf("Type your favorite number:");
  scanf("%d", &yourNumber);
  printf("Your favorite number is: %d", yourNumber);
}

Copy to clipboard
Copy to clipboard

If the user typed in 3, the output would be:

Your favorite number is: 3

Copy to clipboard
Copy to clipboard

Example 2

Here is another example using two variables:

#include <stdio.h>

int main(void) {
  int yourNumber;
  char yourLetter;

  printf("Type your favorite number and letter:");
  scanf("%d%c", &yourNumber, &yourLetter);
  printf("Your favorite number is: %d and your favorite letter is: %c", yourNumber, yourLetter);
}

Copy to clipboard
Copy to clipboard

If the user typed in 4Bh, the output would be:

Type your favorite number and letter:Your favorite number is: 48 and your favorite letter is: h

Copy to clipboard
Copy to clipboard