---
title: 1.23 Expressions and Statements Basics
description: "An **expression** is a combination of operands and operators that produces a value. A **statement** is a complete instruction that controls execution or performs an operation. ``` #include int main() { int a = 10; int b = 20; a…"
url: "https://edcret.in/docs/c-programming/basic-refreshers/1-23-expressions-and-statements-basics/"
updated: "2026-09-06"
category: C Programming / Basic Refreshers
---

# 1.23 Expressions and Statements Basics

An **expression** is a combination of operands and operators that produces a value. A **statement** is a complete instruction that controls execution or performs an operation.

```
#include <stdio.h>

int main()
{
    int a = 10;
    int b = 20;

    a + b;

    a = a + b;

    printf("%d\n", a);

    return 0;
}
```

### Example Output

```
30
```

### Explanation

The expression:

```
a + b
```

produces the value `30`, but the result is not used.

The expression:

```
a = a + b
```

contains an addition expression and an assignment operation. The resulting value is assigned to `a`.

A semicolon turns an expression into an **expression statement**:

```
a + b;
```

C also has other types of statements, including compound statements, selection statements, iteration statements, and jump statements.

### Basic Statement Categories

| Category | Examples | Purpose |
| --- | --- | --- |
| Expression statement | `a = 10;` | Evaluates an expression |
| Compound statement | `{ ... }` | Groups multiple statements |
| Selection statement | `if`, `switch` | Selects execution paths |
| Iteration statement | `while`, `do`, `for` | Repeats statements |
| Jump statement | `break`, `continue`, `goto`, `return` | Transfers control |

### Expressions and Statements

| Expression | Statement |
| --- | --- |
| Produces a value or designates an object/function | Represents a complete executable construct |
| Can be part of a larger expression | Can contain one or more expressions |
| Example: `a + b` | Example: `a = a + b;` |
| Does not necessarily end with `;` | An expression statement ends with `;` |

A compound statement is a block enclosed by braces:

```
{
    int number = 10;
    printf("%d\n", number);
}
```

The declarations and statements inside the braces form a single compound statement.