c scanf function

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Index

1. Single Input
2. Multiple Input
3. Take String Input
4. [[#scanf-limitations|scanf Limitations]]
   • Trick to solove scanf limitation

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Single Input

To get user input, you can use the scanf() function, example:

// Create an integer variable that will store the number we get from the user  
int myNum;  
  
// Ask the user to type a number  
printf("Type a number: \n");  
  
// Get and save the number the user types  
scanf("%d", &myNum);  
  
// Output the number the user typed  
printf("Your number is: %d", myNum);

• The scanf() function takes two arguments:
  1. the C Format Specifiers of the variable
  2. the C Variables And Constants where the input will be saved

oss: if the input is not accepted, the variable won’t be saved oss: you can specify the input text

scanf("(%d-%d)", %x, %y);

The input from the user must follow the same sintax:

(12-13)

[! warning] Note: it’s better to not inset spaces inside the scanf sintax

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Multiple Input

The scanf() function also allow multiple inputs (an integer and a character in the following example):

// Create an int and a char variable  
int myNum;  
char myChar;  
  
// Ask the user to type a number AND a character  
printf("Type a number AND a character and press enter: \n");  
  
// Get and save the number AND character the user types  
scanf("%d %c", &myNum, &myChar);
  
// Print the number  
printf("Your number is: %d\n", myNum);  
  
// Print the character  
printf("Your character is: %c\n", myChar);

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Take String Input

You can also get a string entered by the user:

// Create a string  
char firstName[30];  
  
// Ask the user to input some text  
printf("Enter your first name: \n");  
  
// Get and save the text  
scanf("%s", firstName);  
  
// Output the text  
printf("Hello %s", firstName);

[! warning] Note: When working with strings in scanf():

• you must specify the size of the string/array
• you don’t have to use the reference operator (&).

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scanf Limitations

scanf considers space (whitespace, tabs, etc) as a terminating character,

• which means that it can only display a single word (even if you type many words).

Example:

char fullName[30];  
  
printf("Type your full name: \n");  
scanf("%s", &fullName);  
  
printf("Hello %s", fullName);  
  
// Type your full name: John Doe  
// Hello John

From the example above, you would expect the program to print “John Doe”, but it only prints “John”.

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kikketta To Solve scanf Limitations

Using this metod you can reed more of one word at the time

#include <stdio.h>
 
int main() 
{
	char line[100];
	
	printf("Enter a line of text: ");
	scanf("%[^\n]", line);
	printf("You entered: %s\n", line);
	
	return 0;
}

In this example, we declare a character array line of size 100 to store the user’s input. We use the %[^\n] format specifier to read a string with spaces, which tells scanf to read all characters up to (but not including) a newline character ('\n').

Note:

We are basicly ignoring all escaping character but not inlcluding \n (new line)

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