Inputs and Outputs in C Language:
Inputs and Outputs in C
C provides various functions for input and output operations. The most commonly used functions for this purpose are printf() and scanf().
printf() Function
The printf() function is used to print messages and values to the standard output (usually the console). Here are its main uses:
Printing a Message
To print a message, simply pass the message string to the printf() function:
<![CDATA[#include <stdio.h>
int main() {
printf("Hello, World!\n");
return 0;
}]]>
Printing a Value
To print a value, use a control string that specifies the type of the value and pass the value as an argument to the printf() function:
<![CDATA[#include <stdio.h>
int main() {
int a = 5;
float b = 3.14;
char c = 'A';
printf("Integer: %d\n", a);
printf("Float: %.2f\n", b);
printf("Character: %c\n", c);
return 0;
}]]>
Control Strings
Control strings are used to specify the type of the values to be printed. Here are some commonly used control strings:
| Control String |
Type |
Description |
%d |
int |
Prints an integer |
%f |
float |
Prints a floating-point number |
%.2f |
float |
Prints a floating-point number with 2 decimal places |
%c |
char |
Prints a character |
%s |
char* |
Prints a string |
Escape Sequences
Escape sequences are used to represent special characters in a string. Here are some commonly used escape sequences:
| Escape Sequence |
Description |
\\n |
Newline |
\\t |
Tab |
\\\\ |
Backslash |
\\\" |
Double quote |
\\' |
Single quote |
scanf() Function
The scanf() function is used to read input from the standard input (usually the console). Here are its main uses:
Reading an Integer
<![CDATA[#include <stdio.h>
int main() {
int a;
printf("Enter an integer: ");
scanf("%d", &a);
printf("You entered: %d\n", a);
return 0;
}]]>
Reading a Float
<![CDATA[#include <stdio.h>
int main() {
float b;
printf("Enter a float: ");
scanf("%f", &b);
printf("You entered: %.2f\n", b);
return 0;
}]]>
Reading a Character
<![CDATA[#include <stdio.h>
int main() {
char c;
printf("Enter a character: ");
scanf(" %c", &c); // Note the space before %c to skip any whitespace
printf("You entered: %c\n", c);
return 0;
}]]>
Reading a String
<![CDATA[#include <stdio.h>
int main() {
char str[100];
printf("Enter a string: ");
scanf("%s", str);
printf("You entered: %s\n", str);
return 0;
}]]>
Examples
Here are some examples of using printf() and scanf() in a C program:
<![CDATA[#include <stdio.h>
int main() {
int a;
float b;
char c;
char str[100];
printf("Enter an integer: ");
scanf("%d", &a);
printf("You entered integer: %d\n", a);
printf("Enter a float: ");
scanf("%f", &b);
printf("You entered float: %.2f\n", b);
printf("Enter a character: ");
scanf(" %c", &c); // Note the space before %c to skip any whitespace
printf("You entered character: %c\n", c);
printf("Enter a string: ");
scanf("%s", str);
printf("You entered string: %s\n", str);
return 0;
}]]>