C Academy · Lesson

Operator Precedence

Evaluation order.

Lesson 4 of 413 steps

Operator Precedence is a free C Academy lesson on CoddyKit. This is lesson 4 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, and your progress syncs across the web and the CoddyKit app. The C Academy course includes 4 lessons in total.

Why Precedence Matters

Precedence decides which operator runs first in an expression with several operators. It mirrors normal math: multiplication before addition.

#include <stdio.h>
int main(void) {
    printf("%d\n", 2 + 3 * 4);
    return 0;
}

Parentheses Override

Parentheses force evaluation order. Use them to make intent clear and override defaults.

#include <stdio.h>
int main(void) {
    printf("%d\n", (2 + 3) * 4);
    return 0;
}

Arithmetic Precedence

Among arithmetic operators: * / % bind tighter than + -. The high-precedence ones run first.

#include <stdio.h>
int main(void) {
    int r = 10 - 2 * 3;
    printf("r = %d\n", r);
    return 0;
}

Associativity

When operators share precedence, associativity decides direction. Most arithmetic is left-to-right.

#include <stdio.h>
int main(void) {
    int r = 20 / 4 / 2;
    printf("r = %d\n", r);
    return 0;
}

Right Associativity of Assignment

Assignment groups right to left. That is why a = b = 5 assigns 5 to b first, then a.

#include <stdio.h>
int main(void) {
    int a, b;
    a = b = 5;
    printf("a = %d, b = %d\n", a, b);
    return 0;
}

Comparisons vs Arithmetic

Arithmetic binds tighter than relational operators, so a + b > c computes a + b first.

#include <stdio.h>
int main(void) {
    int a = 2, b = 3, c = 4;
    printf("%d\n", a + b > c);
    return 0;
}

Relational vs Logical

Relational operators bind tighter than &&, which binds tighter than ||.

#include <stdio.h>
int main(void) {
    int x = 5;
    if (x > 0 && x < 10)
        printf("single digit positive\n");
    return 0;
}

Unary Before Binary

Unary operators like ! and unary - bind very tightly, applying before binary operators.

#include <stdio.h>
int main(void) {
    int x = 0;
    printf("%d\n", !x + 1);
    return 0;
}

A Tricky Expression

Without parentheses this expression mixes several precedence levels. Trace it carefully.

#include <stdio.h>
int main(void) {
    int r = 2 + 3 * 4 > 10 && 1;
    printf("r = %d\n", r);
    return 0;
}

When in Doubt, Parenthesize

Good C code uses parentheses liberally. They cost nothing at runtime and prevent subtle bugs.

#include <stdio.h>
int main(void) {
    int a = 1, b = 2, c = 3;
    if ((a < b) && (b < c))
        printf("ascending\n");
    return 0;
}

Precedence in Practice

Here precedence lets us write a clean formula without extra parentheses.

#include <stdio.h>
int main(void) {
    int base = 10, rate = 2, hours = 3;
    int pay = base + rate * hours;
    printf("pay = %d\n", pay);
    return 0;
}

Quick Check

Test your understanding of operator precedence.

Answer it in the interactive lesson

Recap: Operator Precedence

You learned how C orders operators.

* / % before + -
Arithmetic before relational before logical
Most operators are left-associative, assignment is right-associative
Unary operators bind tightly
Parentheses make intent explicit

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Frequently Asked Questions

Is the “Operator Precedence” lesson free?

Yes — the full text of “Operator Precedence” is free to read here on the web. 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. The C Academy course includes 4 lessons in total.

What will I learn in “Operator Precedence”?

Evaluation order. 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, so you can start here or from the beginning and move at your own pace. This is lesson 4 of 4.

How long does the “Operator Precedence” 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?

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