Difference between a signed int and an unsigned int C programming

Difference Between signed int and unsigned int in C

In C programming, int is a data type used to store integer values. There are two primary types of int in C: signed int and unsigned int. Understanding the difference between these two types is crucial for effective programming and memory management.

Signed int

A signed int can represent both positive and negative integers. It typically uses the most significant bit (MSB) as a sign bit:

• Positive Range: From 0 to 2^(n-1) - 1
• Negative Range: From -2^(n-1) to -1

For example, on a 32-bit system:

• Positive Range: 0 to 2,147,483,647
• Negative Range: -2,147,483,648 to -1

Unsigned int

An unsigned int can only represent non-negative integers. It does not use any bits for the sign, so all bits are used to represent the value:

• Range: From 0 to 2^n - 1

For example, on a 32-bit system:

• Range: 0 to 4,294,967,295

Comparison of signed int and unsigned int

Type	Range of Values	Uses
signed int	-2,147,483,648 to 2,147,483,647	When you need to represent both positive and negative values.
unsigned int	0 to 4,294,967,295	When you only need to represent non-negative values and want to utilize the entire range for positive values.

Code Example

Here’s an example program that demonstrates the use of signed int and unsigned int:

#include <stdio.h>

int main() {
    signed int si = -12345;
    unsigned int ui = 12345;

    printf("Signed int: %d\n", si);
    printf("Unsigned int: %u\n", ui);

    return 0;
}

This program prints a value for both signed int and unsigned int to show the difference.

Example Output:
When executed, the output will be:

Signed int: -12345
Unsigned int: 12345

Why Use unsigned int?

Choosing unsigned int can be beneficial when you need to work with large positive values and do not need to represent negative numbers. This is often used in situations where you are working with binary data, counts, or memory addresses.