---
title: 1.26 const Variables
description: "The `const` qualifier makes an object non-modifiable through the declared object. It is commonly used when a value should remain unchanged after initialization. ``` #include int main() { const int maximum = 100; const float pi = 3.14159f; printf(\"%d\\n\", maximum);…"
url: "https://edcret.in/docs/c-programming/basic-refreshers/1-26-const-variables/"
updated: "2026-09-06"
category: C Programming / Basic Refreshers
---

# 1.26 const Variables

The `const` qualifier makes an object non-modifiable through the declared object. It is commonly used when a value should remain unchanged after initialization.

```
#include <stdio.h>

int main()
{
    const int maximum = 100;
    const float pi = 3.14159f;

    printf("%d\n", maximum);
    printf("%.5f\n", pi);

    return 0;
}
```

### Example Output

```
100
3.14159
```

### Explanation

The variables are declared with `const`:

```
const int maximum = 100;
const float pi = 3.14159f;
```

Their values cannot be modified through these declarations:

```
maximum = 200;   /* Invalid */
pi = 3.14f;      /* Invalid */
```

A `const` object should normally be initialized when it is declared:

```
const int value = 10;
```

A `const` qualifier applies to the declared type and does not necessarily make every object or memory location involved in an expression immutable.

For example, a pointer can point to `const` data:

```
const int *ptr;
```

Here, the data accessed through `ptr` cannot be modified through `ptr`, but the pointer itself can be changed to point somewhere else. Pointer qualifiers are covered separately in the pointer and type-qualifier sections.