Console Input Output Functions in C

C language has a collection of functions that can be used in a program with the required number of arguments written in parentheses. Console Input Output Functions are also included in the user program by using the header file <stdio.h> which stands for standard input-output. header. Keyboard and screen together is called Console. There are major two types of Console Input Output Functions in the C programming language.
1. Formatted input/output functions
2. Character input/output functions

Formatted input/output functions:

scanf() Function :

scanf() function is used to read/input values of variables using the standard input device such as keyboard. It has the following the syntax :

scanf("format string", &variable1,&variable2,&variable3,...&variablen);

where “format string” is the control string which represents the format specification, the symbol & (ampersand) which represents the memory address where the variable value is to be stored.

Example :

1. scanf("%d%d", &a,&b); // to read value of <strong>int</strong> variables a and b.
2. scanf("%f%f", &a,&b); // to read value of <strong>float</strong> variables a and b.
3. scanf("%c", &school); // to read value <strong>char</strong> value for variable school.
4. scanf("%s", str); // to read a string of <strong>char</strong> variable str.

format specifiers

printf() Function:

printf() function is used to print/display values of variables using the standard output device such as monitor. It has the following syntax:

("format string", variable1,variable2,variable3,...variablen);

where variable1,variable2,variable3,…variablen are variables whose values are to be displayed in the monitor.
1. printf("%d", a); // to print value of int variables a.
2. printf("%f", x); // to print value of float variables x.

Character input/output functions:

getch() Function :

getch() function is used to read a character from the keyboard and it does not expect the enter key press. It has the following syntax :

ch=getch(); // where ch is a char variable.

Example:
char ctr;
ctr=getch();

getchar() Function:

getchar() function is used to read one character at a time from the standard input device such as keyboard. It has the following syntax :

ch=getchar(); // where ch is a char variable.

putchar() Function:

putchar() function is used to display one character at a time on the monitor screen. It has the following syntax :

putcher(ch); // where ch is a char variable.
Example :
char c='M';
putchar(c);

putch() Function:

putch() function is used to display a character on the monitor screen.It has the following syntax :

putch(ch); // where ch is a char variable.
Example:
char c='s';
putch(c);

getche() Function:

getche() function is used to read a character from the keyboard without expecting the enter key press. It has the following syntax :

ch=getche(); // where ch is a char variable.

Example:
              char ctr;
              ctr=getche();

gets() Function:

gets() function is used to read a string of characters including white spaces. It has the following syntax :

gets(str); // where str is a character string variable.
Example :
char str[15];
gets(str);

puts() Function :

puts() function is used to display a character string on the monitor screen. It has the following syntax :

puts(str); // where str is a string (array of characters)
Example :
char str[20]=" Hello World"
puts(str);

clrscr() Function:

clrscr() function is used to clear the monitor screen. It has the following syntax :

clrscr();
Note: The header file <conio.h> must included to use this function in a program.