Input output(I/O)
Input means providing or inserting some data that is to be used in a program.
Output means to display the data on the screen or write it in a file.
There are many C built-in function that are used to take in data and display the data from a program as a result.
printf() and scanf() functions
printf() and scanf()stdio.h.
printf() takes the values given to it and display it on a screen.scanf() is used to take in user input and store it in some variable to use it in a program.
Example to show the use of printf() and scanf() in a C program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | #include <stdio.h> void main() { //defining a variable int i; /*Displaying to the user to enter value */ printf("Enter the Value: "); /*reading the value*/ scanf("%d", &i); /*Displaying the entered number as a output.*/ printf("\nEntered number is: %d", i); } |
The output of printf() and scanf() in C.
1 2 3 | Enter the Value: 489 Entered number is: 489 |
The following table shows the use of %d, %f, etc in a above program.
| Format String | Meaning |
|---|---|
%d | Scan or print an integer as signed decimal number |
%f | Scan or print a floating point number |
%c | scan or print a character |
%s | scan or print a character string |
getchar() & putchar() functions
getchar() is used to read a character from the terminals(keyboard) and reads only a single character at a time.putchar() is used to write a character on the screen. This is mainly used in File handling in C.
Both the function only displays one character at a time so if the user needs to display it more than one time then it needs to be used with loops.
Example to show the use of getchar() & putchar()
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | #include <stdio.h> void main() { int ch; printf("Enter a character you want: "); //taking character as an input ch = getchar(); printf("The Entered character is: "); //Display the character putchar(ch); } |
The output of getchar() & putchar() in C.
1 2 | Enter a character you want: A The Entered character is: A |