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Printf & scanf in C Language
The printf() and scanf() functions are used for input and output in C language. Both functions are inbuilt library functions, defined in stdio.h (header file).
printf() function :

The printf() function is used for output. It prints the given statement to the console.

The general form of printf() function is given below :

  Syntax :
printf("format string", list of variables);
  Example :
printf(“%d %d”,a,b);

The formatted string represents, what format we want to display on the screen with the list of variables. The format string can be following table :

Data Type Conversion format string
Integer short integer %d or % i
short unsigned % u
long signed % ld
long unsigned % lu
unsigned hexadecimal % x
unsigned octal %O
Real float % f or % g
double %lf
signed character %c
unsigned char %c
string %s
scanf() function :

This function is used to read values using keyboard. It is used for runtime assignment of variables.

The general form of scanf( ) is :

  Syntax :
scanf("format string", list_of_addresses_of_Variables ); 

The format string contains - Conversion specifications that begin with % sign

  Example :
scanf(“%d %f %c”, &a, &b, &c);

& ” is called the address operator, in scanf( ) the “ & ” operator indicates the memory location of the variable. So that the value read would be placed at that location.

Program : Let's see a simple example of C language that gets input from the user and prints the square of the given number.

void main()
int number;  

printf(“enter a number:”);  
printf(“square of number is:%d “,number*number);  
Output :
enter a number: 5
square of number is: 25

The scanf("%d", &number) statement reads integer number from the console and stores the given value in number variable.

The printf("square of number is:%d ",number*number) statement prints the square of number on the console.

Program : Let's see a simple example of input and output in C language that prints addition of 2 numbers.

void main()
int x=0,y=0,result=0;  
printf(“Enter first number : ”);  
printf(“Enter second number : ”);  
printf(“Sum of 2 numbers : %d “,result);    
Output :
Enter first number : 9
Enter second number : 27
Sum of 2 numbers : 36