Learn C, C++ Programming

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• printf() and scanf() functions are inbuilt library functions in C which are available in C library by default. These functions are declared and related macros are defined in “stdio.h” which is a header file.
• We have to include “stdio.h” file as shown in below C program to make use of these printf() and scanf() library functions.

……

1. C printf() function:

• printf() function is used to print the “character, string, float, integer, octal and hexadecimal values” onto the output screen.
• We use printf() function with %d format specifier to display the value of an integer variable.
• Similarly %c is used to display character, %f for float variable, %s for string variable, %lf for double and %x for hexadecimal variable.
• To generate a newline,we use “n” in C printf() statement.

Note:

• C language is case sensitive. For example, printf() and scanf() are different from Printf() and Scanf(). All characters in printf() and scanf() functions must be in lower case.

Example program for C printf() function:

#include <stdio.h>

int main()
{
   char  ch = 'A';
   char  str[20] = "cprogramming.mynetworkip.com";
   float flt = 10.234;
   int no = 150; 

   double dbl = 20.123456;
   printf("Character is %c n", ch);
   printf("String is %s n" , str);
   printf("Float value is %f n", flt);
   printf("Integer value is %dn" , no);

   printf("Double value is %lf n", dbl);
   printf("Octal value is %o n", no);
   printf("Hexadecimal value is %x n", no);

   return 0;

}

You can see the output with the same data which are placed within the double quotes of printf statement in the program except

• %d got replaced by value of an integer variable  (no),
• %c got replaced by value of a character variable  (ch),
• %f got replaced by value of a float variable  (flt),
• %lf got replaced by value of a double variable  (dbl),
• %s got replaced by value of a string variable  (str),
• %o got replaced by a octal value corresponding to integer variable  (no),
• %x got replaced by a hexadecimal value corresponding to integer variable
• n got replaced by a newline.

2. C scanf() function:

• scanf() function is used to read character, string, numeric data from keyboard
• Consider below example program where user enters a character. This value is assigned to the variable “ch” and then displayed.
• Then, user enters a string and this value is assigned to the variable “str” and then displayed.

Example program for printf() and scanf() functions in C:

#include <stdio.h>

int main()
{
    char ch;
    char str[100];

    printf("Enter any character n");
    scanf("%c", &ch);
    printf("Entered character is %c n", ch);

    printf("Enter any string ( upto 100 character ) n");
    scanf("%s", &str);
    printf("Entered string is %s n", str);
}

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