---
title: 4.3 Integer Conversion
description: "Integer conversion occurs when a value of one integer type is converted to another integer type. The result depends on the destination type and whether it can represent the original value. ``` #include int main(void) { int number = 130;…"
url: "https://edcret.in/docs/c-programming/type-conversion/4-3-integer-conversion/"
updated: "2026-10-27"
category: C Programming / Type Conversion
---

# 4.3 Integer Conversion

Integer conversion occurs when a value of one integer type is converted to another integer type. The result depends on the destination type and whether it can represent the original value.

```
#include <stdio.h>

int main(void)
{
    int number = 130;
    signed char small = number;
    unsigned int positive = -10;

    printf("Original: %dn", number);
    printf("Converted: %dn", small);
    printf("Unsigned: %un", positive);

    return 0;
}
```

### Example Output

On a typical implementation with 8-bit `signed char` using two's-complement representation and 32-bit `unsigned int`:

```
Original: 130
Converted: -126
Unsigned: 4294967286
```

### Explanation

The assignment:

```
signed char small = number;
```

converts the value `130` to `signed char`. If the destination type cannot represent the original value, the result is **implementation-defined** in C17 and earlier. C23 specifies the result differently. The example output reflects a common implementation.

The assignment:

```
unsigned int positive = -10;
```

converts `-10` to `unsigned int`. Unsigned integer conversion produces the value congruent to the original value modulo one more than the maximum value of the destination type.

For a 32-bit `unsigned int`, the result is:\[ 2^{32}-10 = 4294967286 \]

### Integer Conversion Rules

| Conversion | Behavior |
| --- | --- |
| Smaller value to a wider integer type that can represent it | Value is preserved |
| Signed integer to unsigned integer | Result is reduced modulo one more than the unsigned maximum |
| Unsigned integer to a signed integer type that can represent the value | Value is preserved |
| Value outside the destination signed type's range | Result depends on the applicable C standard |
| Wider integer type to a narrower type | Value may change if it is not representable |

Integer conversions can change a value even when no arithmetic operation is performed. The destination type determines how the converted value is represented.