printf Format Specifiers
Print values precisely.
printf Format Specifiers is a free C Academy lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the C Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
What printf Does
printf writes formatted text to the screen. Format specifiers starting with % are replaced by your values.
#include <stdio.h>
int main(void) {
printf("Hello, world!\n");
return 0;
}Printing Integers with %d
Use %d for a signed decimal integer.
#include <stdio.h>
int main(void) {
int age = 30;
printf("Age: %d\n", age);
return 0;
}Printing Floats with %f
Use %f for floating-point values. By default it prints six decimals.
#include <stdio.h>
int main(void) {
double price = 9.5;
printf("Price: %f\n", price);
return 0;
}Printing Characters with %c
Use %c to print a single character.
#include <stdio.h>
int main(void) {
char grade = 'A';
printf("Grade: %c\n", grade);
return 0;
}Printing Strings with %s
Use %s to print a C string (a char array).
#include <stdio.h>
int main(void) {
char name[] = "Alice";
printf("Name: %s\n", name);
return 0;
}Multiple Values
One printf can hold several specifiers; supply the arguments in the same order.
#include <stdio.h>
int main(void) {
char name[] = "Bob";
int age = 25;
printf("%s is %d years old\n", name, age);
return 0;
}Printing a Literal Percent
To print an actual % sign, write %%.
#include <stdio.h>
int main(void) {
int pct = 80;
printf("Battery: %d%%\n", pct);
return 0;
}Hexadecimal and Octal
%x prints in hexadecimal and %o in octal.
#include <stdio.h>
int main(void) {
int n = 255;
printf("hex: %x oct: %o\n", n, n);
return 0;
}Long and Unsigned
Use %ld for long and %u for unsigned int to match the argument type.
#include <stdio.h>
int main(void) {
long big = 1000000L;
unsigned int u = 4000000000u;
printf("%ld %u\n", big, u);
return 0;
}Matching Type to Specifier
The specifier must match the argument type. A mismatch like printing a double with %d is undefined behavior.
#include <stdio.h>
int main(void) {
double d = 3.5;
printf("%f\n", d);
return 0;
}Newlines and Tabs
Escape sequences like \n and \t control layout inside the format string.
#include <stdio.h>
int main(void) {
printf("Col1\tCol2\n");
printf("a\tb\n");
return 0;
}Quick Check
Test your understanding of printf specifiers.
Recap: printf Format Specifiers
You learned how printf formats output.
%dintegers,%ffloats,%cchars,%sstrings%xhex,%ooctal,%uunsigned,%ldlong%%prints a literal percent- Specifier must match argument type
- Escape sequences control layout
Frequently asked questions
Is the “printf Format Specifiers” lesson free?
Yes — the full text of “printf Format Specifiers” is free to read here on the web, and the C Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the C Academy course, upgrade to CoddyKit PRO.
What will I learn in “printf Format Specifiers”?
Print values precisely. You practise C Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start C Academy?
No prior experience is required. C Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “printf Format Specifiers” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this C Academy lesson?
Yes. Every C Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- printf Format Specifiers
- scanf and Input
- Width, Precision, Flags
- Common I/O Pitfalls