printf() in C for Formatted Output

printf() writes formatted output to the standard output stream. It is declared in <stdio.h>. The format string can contain normal text, escape sequences such as \n, and conversion specifications such as %d or %f.

Basic printf() Example Top ↑

#include <stdio.h>

int main(void) {
    printf("Welcome to plus2net\n");
    return 0;
}

Output

Welcome to plus2net

Common Format Specifiers Top ↑

Integer and Floating-Point Output Top ↑

The complete program structure is already shown above, so the next examples focus on the changing declarations and printf() statements.

int count = 25;
double pi = 3.14159;

printf("Integer: %d\n", count);
printf("Float: %.2f\n", pi);

Output

Integer: 25
Float: 3.14

Key change: %.2f requests two digits after the decimal point. The // notes used throughout these examples are C comments.

Characters and Strings Top ↑

char ch = 'A';
char name[] = "plus2net";

printf("Character: %c\n", ch);
printf("String: %s\n", name);

Output

Character: A
String: plus2net

Field Width and Precision Top ↑

double number = 123.456;
printf("%10.2f\n", number);

Output

    123.46

10 is the minimum field width and .2 is the precision for this floating conversion.

Newline and Tab Escape Sequences Top ↑

printf("Line 1\nLine 2\n");
printf("Name\tScore\n");

\n starts a new line and \t inserts a horizontal tab.

Print Individual Characters from a String Top ↑

char text[] = "plus2net";
printf("%c\n", text[3]);
printf("%c\n", text[4]);

Output

s
2

Array indexing starts at zero.

Print a String in Reverse Top ↑

#include <stdio.h>
#include <string.h>

int main(void) {
    char text[] = "plus2net";
    size_t length = strlen(text);

    while (length > 0) {
        length--;
        printf("%c", text[length]);
    }
    printf("\n");
    return 0;
}

Output

ten2sulp

C is case-sensitive. The library function is named printf, not Printf.

Practice Top ↑

1. Display the sum of two integers.
2. Print a four-row growing star pattern.
3. Print a floating value with three digits after the decimal point.

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

About the author   Watch on YouTube

Connect: