Variable assignment

Learn to assign and initialize values to variables.

Variable assignment

Assignment means giving a value to a variable. In C the assignment operator is =. After declaring a variable, you can assign new values as many times as you want:

int x = 5;
x = 10;
x = 20;

Each assignment overwrites the old value with the new one. = means assignment, not equality; for equality use ==.

Type mismatch

When assigning with mismatched types, C silently converts, which can cause surprising results:

int x = 3.7;   // x = 3
double y = 5;  // y = 5.0

Converting double to int loses the decimal part. The other way around, the value becomes a decimal automatically. Take warnings seriously; we will see the cast operator in later lessons.

Exercise Declare and reassign

Declare an int x with value 5. Then reassign x to 10 and print it with printf using %d.

Show example solution

#include <stdio.h>

int main(void) {
    int x = 5;
    x = 10;
    printf("%d", x);
    return 0;
}

Test yourself

Reassignment
```
int x = 5;
x ____ 10;
```
Show answer
```
int x = 5;
x = 10;
```
Final value of x
```
int x = 5;
x = 10;
printf("%d", x);
```
- 10
- 5
- 15
- 50
Show answer

10 — x was set to 5, then reassigned to 10. The final value is 10.
Match the operators

=

Assignment
==

Equality
+

Addition
-

Subtraction

Next lesson: const

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