1.Input output using printf() and scanf() function.

/* C Language basic program that shows working of I/O printf() and scanf() Functions */
#include <stdio.h>
int main()
{
char name[30];
char ch;
printf("\nEnter Your Name");
scanf("%s", &name);
printf("Your Name is= %s ", name);
printf("Enter any character ");
scanf("%c", &ch);
printf("Entered character is =%c", ch);
}
Output: Enter Your Name
James
Your name is=James
Enter any character
C
Entered character is =C

Program Explanation:
In the program given above The two character variables are declared i.e. name and ch.
char name[30];--> name is declared as character array of 30 character which can store 30 alphabates or character.
Memory allocated by name is 30 bytes.
char ch; here ch is declared as character which can store single character and occupy single byte of memory.
next we have the statement.

The printf() shows message "Enter Your name" and program waits until name is not entered.
We have Enterd the name : "James".
The Entered name get scaned by scanf("%s", &name); and stores it in name variable.
next the printf("Your Name is= %s ", name); shows the output "Your name is =James".
%s in printf() is the format specifiers used to place string value.
The format specifier %s is subtituted by the value of name variable i.e "James"
similarly We have Entered character 'C' and it has stored in character variable ch , which is processed by
printf("Enter any character ");
scanf("%c", &ch);
and finaly output shown is "Entered character is=C"

2. Input output using gets() and puts() function.

/* An example to read a sentence(string) using gets() function and print it on the console using puts() function */
#include <stdio.h>
#include <string.h>
int main()
{
char sentence[50];
printf("\nEnter your favorite sentence:");
gets(sentence);    /*read input sentence from entered by the user*/
printf("\n your favorite sentence is:\n");
puts(sentence);    /*display the sentence on console */
return 0;
}
When the above code is executed, it produces the following results:
Enter your favorite sentence:
I Love C Language.
Your Favorite Sentence is: I Love C Language.

3.Input output using getchar() and putchar() function in C.

#include<stdio.h>
#include <ctype.h>
int main()
{ char chr;
printf ("\n Enter any character ( If you want to exit press #) ");
while (chr != '#') /* accept the number till the user does not enter the # to exit from the loop. */
{
chr = getchar();
printf (" \n You have entered the character : ");
putchar (chr); // prints a single character
printf ("\n");
}
return 0;
}
Output:
Enter any character ( If you want to exit.. press #)
A
You have entered the character: A
B
You have entered the character: B
C
You have entered the character:C