Declaring arrays
- C course
- Beginner
- Lesson 53/116
- 4 min
Learn to declare and initialize arrays with int[] and double[].
Declaring arrays
An array holds several values of the same type under one name. In C the array size goes in square brackets; the type comes first.
int scores[5];
double prices[10];
char name[32];Here scores holds 5 integers, prices 10 decimals, name 32 characters. Arrays occupy contiguous memory; this makes access fast. After declaring, you assign values by index using square brackets.
Initializing arrays
You can give values when you declare the array. Write the values in a list inside braces.
int scores[5] = {85, 92, 78, 90, 88};
double temps[3] = {36.5, 37.0, 36.8};
char vowels[5] = {'a', 'e', 'i', 'o', 'u'};If you omit the size the compiler counts the list: int scores[] = {85, 92, 78}; makes a three-element array. With fewer values, the rest become zero; useful for safe initialization.
Practice Declare three scores and print
Write a C program. Declare int scores[3] = {85, 92, 78};. Print the three values with printf("%d %d %d\n", scores[0], scores[1], scores[2]);. Put #include <stdio.h> at the top.
Starter code
#include <stdio.h>
int main(void) {
// Declare scores and print the three values
return 0;
}Sample solution
#include <stdio.h>
int main(void) {
int scores[3] = {85, 92, 78};
printf("%d %d %d\n", scores[0], scores[1], scores[2]);
return 0;
}Expected output
85 92 78
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 How many values does int scores[5]; hold?
int scores[5];- 1
- 5 Correct answer
- 4
- 6
Explanation: [5] makes a five-element array.
2 Complete the array declaration
int ____[5];int scores[5];Explanation: scores is the array name.
3 Match the array parts
| Term | Meaning |
|---|---|
int |
Type |
scores |
Name |
[5] |
Size |
{1,2,3} |
Initialization |