The modulo operator in C will give the remainder that is left over when one number is divided by another. For example, 23 % 4 will result in 3 since 23 is not evenly divisible by 4, and a remainder of 3 is left over.

If you want to output whether or not a number is divisible by 4, you need to output something other than just the mod result. Essentially, if mod = 0 than you know that one number is divisible by another.

If you want to output whether or not the number is divisible by 4, I would suggest creating a new character that is set to "y" (yes) or "n" (no) depending on the result of the mod operation. Below is one possible implementation to generate a more meaningful output:

#include <stdio.h>
#include <ctype.h>
#include <math.h>

int main()
{
    int my_input[] = {23, 22, 21, 20, 19, 18};
    int n, mod;
    char is_divisible;
    int nbr_items = sizeof(my_input) / sizeof(my_input[0]);

    for (n = 0; n < nbr_items; n++)
    {
        mod = my_input[n] % 4;
        is_divisible = (mod == 0) ? 'y' : 'n';
        printf("%d modulo %d --> %c\n", my_input[n], 4, is_divisible);
    }
}

This will give the following:

23 modulo 4 --> n
22 modulo 4 --> n
21 modulo 4 --> n
20 modulo 4 --> y
19 modulo 4 --> n
18 modulo 4 --> n
Answer from rakeshb on Stack Overflow
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GeeksforGeeks
geeksforgeeks.org › c++ › modulo-operator-in-c-cpp-with-examples
Modulo Operator (%) in C/C++ with Examples - GeeksforGeeks
July 12, 2025 - In C or C++, the modulo operator (also known as the modulus operator), denoted by %, is an arithmetic operator.
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Scaler
scaler.com › home › topics › modulus operator in c
What is Modulus Operator in C? - Scaler Topics
December 19, 2022 - Modulus operator, also called as modulo operator, is a binary arithmatic operator in C language, denoted using % (percentile) symbol Binary means two, that means, it is operated with two operands, both being integers only
People also ask

In what cases do we get an error from the compiler when using the modulo operator?
If p and q are integers, then for p % q: If p is 0, then division by zero generates a compile-time error. If p is some number (integer) and q is 0, then also we get a compile-time error. Also, one cannot use and apply the % operator on an available set of floating numbers (that is float or double). If we try to use this operator with any floating-point variables or even constants, the compiler will generate a compile-time error.
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byjus.com
byjus.com › gate › modulus-operator-in-c
Syntax of Modulus Operator in C
How does the % operator work?
The working of this kind of operator happens on the basis of the value that the end-user receives since it always finds a remainder of the two available numbers/ integers with respect to the numerator and denominator. Remember that we are talking about remainder and not a quotient of the numerator-denominator pair. For example, 9 % 2 will give us 1 as a remainder. It is because when we divide 9 by 2, we get 3 as a quotient, but there remains a remainder of 1.
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byjus.com
byjus.com › gate › modulus-operator-in-c
Syntax of Modulus Operator in C
Top answer
1 of 2
9

The modulo operator in C will give the remainder that is left over when one number is divided by another. For example, 23 % 4 will result in 3 since 23 is not evenly divisible by 4, and a remainder of 3 is left over.

If you want to output whether or not a number is divisible by 4, you need to output something other than just the mod result. Essentially, if mod = 0 than you know that one number is divisible by another.

If you want to output whether or not the number is divisible by 4, I would suggest creating a new character that is set to "y" (yes) or "n" (no) depending on the result of the mod operation. Below is one possible implementation to generate a more meaningful output:

#include <stdio.h>
#include <ctype.h>
#include <math.h>

int main()
{
    int my_input[] = {23, 22, 21, 20, 19, 18};
    int n, mod;
    char is_divisible;
    int nbr_items = sizeof(my_input) / sizeof(my_input[0]);

    for (n = 0; n < nbr_items; n++)
    {
        mod = my_input[n] % 4;
        is_divisible = (mod == 0) ? 'y' : 'n';
        printf("%d modulo %d --> %c\n", my_input[n], 4, is_divisible);
    }
}

This will give the following:

23 modulo 4 --> n
22 modulo 4 --> n
21 modulo 4 --> n
20 modulo 4 --> y
19 modulo 4 --> n
18 modulo 4 --> n
2 of 2
7

I'm sure we know the basic division equation from high school math

dividend = divisor*quotient + remainder

Now:
1. The "/" operator gives us the quotient.
2. The "%" operator gives us the remainder

example:

    say a = 23, b = 4
    a / b = 23 / 4 = 5
    a % b = 23 % 4 = 3

    23 = 4*5 + 3 

Here 4 is the quotient and 3 is the remainder.

If a number is perfectly divisible by a divisor, then remainder is zero.

So:

    20/4 = 5 (quotient)
    20%4 = 0 (remainder)

To test if a no if divisible by 4, the check should be something like if (num % 4 == 0).
Hope this helps!

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Linux Hint
linuxhint.com › c-modulo-operator-examples
Modulo Operator in C – Linux Hint
For example, if we divide 5 by 2, we will get a remainder of 1, where 5 is the dividend, 2 is the divisor, and 1 is the remainder. In C programming language the modulo operator is represented by the percent symbol: %. One example use case of the modulo operator is to find whether the number ...
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BYJUS
byjus.com › gate › modulus-operator-in-c
Syntax of Modulus Operator in C
November 9, 2022 - We use the % to denote this type of operator (it’s the percentile operator). The modulus operator is added in the arithmetic operators in C, and it works between two available operands.
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PrepBytes
prepbytes.com › home › data structure › what does modulo operator do in c / c++?
What does Modulo Operator do in C / C++?
November 29, 2023 - Continue Exploring → ... The modulo operator, represented by the % symbol in C and C++, is a fundamental arithmetic operation that calculates the remainder of a division operation between two numbers.
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Cprogramming
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Modulus Operator in C and C++ - Programming Tutorials - Cprogramming.com
How to begin Get the book · C tutorial C++ tutorial Game programming Graphics programming Algorithms More tutorials
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Delft Stack
delftstack.com › home › howto › modulo in c
The Modulo Operator in C | Delft Stack
March 12, 2025 - The modulo operator, often represented by the percentage symbol (%), is a fundamental tool in C programming. It allows developers to determine the remainder of a division operation between two integers.
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LabEx
labex.io › questions › what-is-the-purpose-of-the-modulo-operator-in-c-136083
What is Modulo Operator in C | LabEx
July 25, 2024 - Its primary purpose is to calculate the remainder of a division operation between two integer values. The modulo operator works by dividing the first operand (the dividend) by the second operand (the divisor) and returning the remainder of the division.
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EDUCBA
educba.com › home › software development › software development tutorials › c programming tutorial › modulus operator in c
Modulus Operator in C | Calculations & Working of Modulus Operator
June 28, 2023 - The % (percentile) operator denotes the modulus operator in C. This modulus operator is added to arithmetic operators. This modulus operator works between 2 operands. The modulus operator finds the division with numerator by denominator, resulting ...
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Wikipedia
en.wikipedia.org › wiki › Modulo
Modulo - Wikipedia
3 days ago - This still leaves a sign ambiguity if the remainder is non-zero: two possible choices for the remainder occur, one negative and the other positive; that choice determines which of the two consecutive quotients must be used to satisfy equation (1). In number theory, the positive remainder is always chosen, but in computing, programming languages choose depending on the language and the signs of a or n. Standard Pascal and ALGOL 68, for example, give a positive remainder (or 0) even for negative divisors, and some programming languages, such as C90, leave it to the implementation when either of n or a is negative (see the table under § In programming languages for details). Some systems leave a modulo 0 undefined, though others define it as a.
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LabEx
labex.io › tutorials › c-use-the-modulus-operator-in-c-435358
How to Use the Modulus Operator in C | LabEx
Learn how to use the modulus operator in C to calculate remainders and perform basic arithmetic operations with integer variables.
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Sololearn
sololearn.com › en › Discuss › 989220 › modulo-and-integer-division-in-c-and-c-languages
Modulo and integer division in C++ and C languages. | Sololearn: Learn to code for FREE!
I think what 4rontender is pointing out clearly is that -n%m in .cpp != -n%m in .py & -n/m in .cpp != -n/m in .py ... c & c++ are hardware related languages. it is searched for the fastest and most direct method to compute modulo. IEEE allows you to: IEEE 754 defines a remainder function where the quotient is a/n rounded according to the round to nearest convention.
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Quora
quora.com › How-do-I-write-a-a-in-C-language-I-kept-looking-for-how-to-write-modulus-in-C-but-all-I-found-was-about-a-b-modulus
How do I write a=|a| in C language? I kept looking for how to write modulus in C but all I found was about a%b modulus.
Answer (1 of 7): Yeah it’s confusing that in regular math we have “modulus” and “modulo”. * modulus (written |a| ) means “take the absolute value” - so if it’s negative, make it positive - and if it’s positive, do nothing.
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Reddit
reddit.com › r/programming › the c/c++ modulus operator
r/programming on Reddit: The C/C++ Modulus Operator
August 4, 2019 - The modulus of any number with respect to a given base has the property that adding or subtracting the base from the original number won't affect the modulus. This, -1 mod 10 is equal to (-1+10) mod 10, which is of course equal to 9. This can be very useful when e.g. determining how much time there should be between some time in the past or present and the next occurrence of a periodic event.
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Examveda
examveda.com › home › c program › c fundamentals › question
Which symbol is used for the 'modulo' operation in C
The symbol used for the 'modulo' operation in C is %. The '%' symbol calculates the remainder when one number is divided by another and is commonly used for tasks such as checking for even or odd numbers and cycling through a range of values.
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Reddit
reddit.com › r/cs50 › can someone explain the modulo operation to me like i'm five? (credit.c)
r/cs50 on Reddit: Can someone explain the modulo operation to me like I'm five? (Credit.c)
April 24, 2020 -

So I'm really struggling with the credit problem in pset1. I'm completely new to coding and computer science and everything but I really want to try doing all of the problems in this class. I had to look up mario and cash to gain some insight into what I've been doing wrong when I approach a problem. With each completed problem the pieces come together in my head a little more than they were before.

Credit has me totally through a loop. It seems like for all of the problems I understand what to use in C as far as loops and what have you but I really struggle with figuring out what like operations I'm supposed to use to tell the program exactly what to do. With the whole modulo operation thing I don't really understand what it's doing and what I have to do to get it to give me the numbers I need. Something tells me I need to use different powers of ten to somehow separate the full credit card number into individual digits but because I don't understand what % 10 is actually doing I can't fully figure out what I need to do.

I'm struggling with trying to decide if I should just skip this problem and try again another time or if I should contemplate it more. With each problem it seems like I struggle with like some kind of mathematical aspect, I feel like there's something that I'm missing but I can't tell if I just how to make myself think about things differently. I feel like I'm making myself crazy about this lol

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Quora
quora.com › What-is-the-difference-between-the-modulo-and-operators-in-C-programming
What is the difference between the modulo and % operators in C programming? - Quora
Answer: I can’t tell what you actually meant to ask but there is no difference between the modulo and % operator in C. The modulo operator is used to calculate the remainder of integer division.