✏️ Explanatory Question
Answer:
printf() is a standard library function
declared in the Syntax
printf("format_string", value1, value2, ...);
| Part | Description |
|---|---|
printf |
Name of the output function. |
format_string |
Text along with format specifiers such as %d, %f, %c, and %s. |
value1, value2... |
Variables or values to be displayed. |
Header File
#include
Before using printf(), you must include the
printf().
Example 1: Print a Simple Message
#include
int main()
{
printf("Hello World");
return 0;
}
Output
Hello World
Example 2: Print Variables
#include
int main()
{
int age = 20;
float marks = 89.5;
char grade = 'A';
printf("Age = %d\n", age);
printf("Marks = %.1f\n", marks);
printf("Grade = %c", grade);
return 0;
}
Output
Age = 20
Marks = 89.5
Grade = A
Common Format Specifiers
| Format Specifier | Data Type | Example Output |
|---|---|---|
%d |
Integer | 25 |
%f |
Float | 45.67 |
%c |
Character | A |
%s |
String | Hello |
%lf |
Double | 123.456 |
%x |
Hexadecimal Integer | 1A |
%% |
Percent Symbol | % |
Return Value of printf()
The printf() function returns the total number of characters
successfully printed on the screen.
#include
int main()
{
int result;
result = printf("Hello");
printf("\nCharacters Printed = %d", result);
return 0;
}
Output
Hello
Characters Printed = 5
RETURN VALUE
printf()
→
Number of Characters Printed
Advantages of printf()
Advantages
- Displays formatted output.
- Supports multiple data types.
- Easy to use and understand.
- Allows multiple values to be printed in one statement.
- Supports escape sequences such as
\nand\t. - Widely used in debugging and user interaction.
Common Mistakes
Avoid These Mistakes
- Forgetting to include
- Using the wrong format specifier.
- Passing an incorrect number of arguments.
- Missing quotation marks around text.
Best Practices
- Always include
- Use the correct format specifier for each data type.
- Use
\nto improve output readability. - Keep output messages meaningful and user-friendly.
Prerequisites
Before Learning This Topic
- Basic understanding of C program structure.
- Knowledge of variables and data types.
- Basic familiarity with functions in C.
- Understanding of header files and the
#includedirective.
Interview Questions
- What is the purpose of the
printf()function? - Which header file contains the declaration of
printf()? - What value does
printf()return? - What is the difference between
printf()andputs()? - What happens if you use the wrong format specifier in
printf()?
Key Takeaway
printf() is a standard library function used to
display formatted output on the console. It is declared in the