printf() and scanf() in C

 Methods In C :

    The scanf() and  printf() functions are used to read the input from the console and output to the console. Both the functions are built-in functions defined in stdio.h(standard input output) header file. C has many built-in library functions. Whenever we use any built-in functions we need to declare the header file to which the built-in function belongs to.

 scanf(): The scanf() function is used to read the input from the console/user.

 syntax: 

 scanf("format specifiers",&variables_list);

 Example: 

 scanf("%d %d", &var1,&var2); [no of specifiers = no of variables]

        %d: %d in scanf allows the function to recognize user input as being of an integer data type.

        &: The ampersand(&) allows us to pass the address[place in memory] of the variable where we store the information that the scanf read. 

printf(): The print() function is used for output to the console.

Syntax: 

printf("format specifiers", variable_list);

 No need for an ampersand(&) symbol in printf().

 Example: 

  printf("%d %d",var1,var2);

Format Specifiers: The format specifiers are used in C for input and output purposes. Using these format specifiers, the compiler can understand that what type of data is in a variable during taking input using the scanf() function and printing using printf() function.        

Format specifier	Type
%d	Signed integer [both positive and negative values]
%i	Unsigned integer [only positive values]
%l	Long integer
%lld	Long long integer
%c	character
%f	Float values
%lf	Double values
%Lf	Long double
%s	String

Examples:

    1. write a program for the input of two variables and print those variables.

        

         program:

        

     

        Output:

     

    Explanation: For every variable input or output we must specify its corresponding format specifier. The output of the variables format depends on its declaration. 

2. write a program to display numbers from 0 to a given number.

    

      program:

        

  

     Output:

  

 Rules to remember while writing the code :

    

      1. Declare variables before they used in the code.

      2. Be thorough with the syntaxes.

      3. Don't forget to put the semicolon at the end of each statement;

      4. Follow the indentation for a better understanding and to modify code easily.

      5. For every block there must be opening and closing curly braces. 

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