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DATA INPUT AND OUTPUT 1
DATA INPUT AND
OUTPUT
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• Define input output statements
• Explain function of input output
statements
• Create and modify input output
file in programme
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C Environment
C environment
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input device output device
error device
stdinstdout
stderr
input/output operation take places as a stream
of character
#include<stdio.h> includes the contents of
standard input-output file, stdio.h at compile
time (contains definitions of stdin, stdout,
stderr)
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C provides standard functions, scanf() and
printf() for performing formatted input and
output
Input data may contain a mixed mode data:
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DATA TYPES EXAMPLE
float floating point 101.7, 0.5, 2.36
double floating point 2.365, 75.666, 0.12222
int decimal number 225, 3, 75, 9662
char character a, f, apple, 15DET09F1002
printf() and puts()
printf() function
used for formatted output to standard output device that is screen
general form:
e.g:
printf(“%d%d%d\n”,456,456,456)
Output: 456456456
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printf(“format_specifier”,variable_list1,variable_list2,…)
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Codes Meaning
\b Back space
\f Form feed
\n New line
\r Carriage return
\t Horizontal tab
\” Double quote mark
\’ Single quote mark
\0 Null
\\ Back slash
\v Vertical tab
\a Alert
\o Octal constant
\x Hexadecimal constants
puts()
to display a string contained in a string
variable
general form:
e.g:
char str[20]=“I am going to England”;
puts(str);
if str has the string “I am going to Englad”, puts(str) would
display the entire string “I am going to England” and
moves the cursor to the beginning of the next line
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int puts (char*)
scanf() and gets()
scanf() function
used for formatted input from standard input device that is keyboard
general form:
e.g:
printf(“Please enter a number”);
scanf(“%d”,&number1)
Output: Please enter a number 15
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scanf(“format specifier”,variable_list1,variable_list2,…)
gets()
to accept string up to a new line character into
a string variable
general form:
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char*gets (char *);
To illustrate gets() and puts()
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#include<stdio.h>
#include<conio.h>
void main()
{
char words[40];
clrscr();
printf(“Enter a line of text: “);
gets (words);
printf(“\nThe line of text entered is “);
puts (words);
}
Enter a line of text: I love programming
The line of text entered is I love programming
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printf() STATEMENT OUTPUT
printf(“Line 1”);
printf(“Line 2”);
printf(“Line 3”);
Line1Line2Line3
The newline character (\n) must be include whenever
the cursor have to move to the next line
printf() STATEMENT OUTPUT
printf(“Line 1\n”);
printf(“Line 2\n”);
printf(“Line 3\n”);
Line1
Line2
Line3
printf() STATEMENT OUTPUT
printf(“Line 1”);
printf(“\nLine 2\n”);
printf(“Line 3”);
Line1
Line2
Line3
Specifies the field in which the data has to
be entered
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code meaning
%c Single character
%d Decimal integer
%e Floating point value
%f Floating point value
%o Octal value
%x Hexadecimal value
%s A string
%u Unsigned integer
int d;
to accept a value into a variable n of int type
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scanf(“%d”,&n); Which is %d is the format specifier for int
Variable n
char c;
to accept a value into a variable c of char type
scanf(“%c”, &c); Note that the format specified used is %c
Variable c
float f;
to accept a floating point value into the variable f
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scanf(“%f”, &f); Note that the format specified used is %f
Variable f
To read values into three variable i, f, and c of
type int, float and char using a single statement
scanf(“%d%f%c”, &i,
&f, &c);
Note that the order of the format
specifiers matches with that of the
variable
int d;
To display the value of the variable n of int type
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printf(“%d”,n); Which is %d is the format specifier for int
Variable n
char c;
To display the character stored in the variable c
printf(“%c”,c); Note that the format specified used is %c
Variable c
float f;
to display the floating point value stored in the variable f
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printf(“%f”,f); Note that the format specified used is %f
Variable f
To display the value stored in three variable i, f, and c of type int, float and char using a single statement
printf(“%d%f%c”,i,f,
c);
Note that the order of the format
specifiers matches with that of the
variable
To illustrate simple printf() and scanf()
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#include<stdio.h>
void main()
{
int number_1, number_2, total;
printf(“Enter first number: “);
scanf(“%d”, &number_1);
printf(“Enter second number: “);
scanf(“%d”, &number_2);
total= number_1 + number_2;
printf(“\nTotal for first and second number : %d”, total);
}
Enter first number : 15
Enter second number :65
Total for first and second number :80
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