Variable assignment
- C course
- Beginner
- Lesson 8/116
- 4 min
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 = 5.0Converting 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.
Practice Declare and reassign
Declare an int x with value 5. Then reassign x to 10 and print it with printf using %d.
Starter code
// declare int x, then assign 10 and printSample solution
#include <stdio.h>
int main(void) {
int x = 5;
x = 10;
printf("%d", x);
return 0;
}Expected output
10
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Reassignment
int x = 5;
x ____ 10;int x = 5;
x = 10;Explanation: x = 10; assigns a new value to x.
2 Final value of x
int x = 5;
x = 10;
printf("%d", x);- 10 Correct answer
- 5
- 15
- 50
Explanation: x was set to 5, then reassigned to 10. The final value is 10.
3 Match the operators
| Term | Meaning |
|---|---|
= |
Assignment |
== |
Equality |
+ |
Addition |
- |
Subtraction |