Jagged Array or Array of Arrays in C with Examples
Prerequisite: Arrays in C
Jagged array is array of arrays such that member arrays can be of different sizes, i.e., we can create a 2-D array but with a variable number of columns in each row. These type of arrays are also known as Jagged arrays.
Example:
arr[][] = { {0, 1, 2}, {6, 4}, {1, 7, 6, 8, 9}, {5} };
Below are the methods to implement the jagged array in C:
- Using array and a pointer (Static Jagged Array)
- First declare 1-D arrays with the number of rows you will need,
- The size of each array (array for the elements in the row) will be the number of columns (or elements) in the row,
- Then declare a 1-D array of pointers that will hold the addresses of the rows,
- The size of the 1-D array is the number of rows you want in the jagged array.
Below is the implementation of the above approach:
Example:// C program to show the
// implementation of Jagged Arrays
#include <stdio.h>
#include <stdlib.h>
int
main()
{
int
row0[4] = { 1, 2, 3, 4 };
int
row1[2] = { 5, 6 };
int
* jagged[2] = { row0, row1 };
// Array to hold the size of each row
int
Size[2] = { 4, 2 }, k = 0;
// To display elements of Jagged array
for
(
int
i = 0; i < 2; i++) {
// pointer to hold the address of the row
int
* ptr = jagged[i];
for
(
int
j = 0; j < Size[k]; j++) {
printf
(
"%d "
, *ptr);
// move the pointer to the
// next element in the row
ptr++;
}
printf
(
"\n"
);
k++;
// move the pointer to the next row
jagged[i]++;
}
return
0;
}
Output:1 2 3 4 5 6
- Using an array of pointer (Dynamic Jagged Array)
- Declare an array of pointers (jagged array),
- The size of this array will be the number of rows required in the Jagged array
- Then for each pointer in the array allocate memory for the number of elements you want in this row.
Below is the implementation of the above approach:
Example:// C program to show the
// implementation of Jagged Arrays
#include <stdio.h>
#include <stdlib.h>
int
main()
{
// 2 Rows
int
* jagged[2];
// Allocate memory for elements in row 0
jagged[0] =
malloc
(
sizeof
(
int
) * 1);
// Allocate memory for elements in row 1
jagged[1] =
malloc
(
sizeof
(
int
) * 3);
// Array to hold the size of each row
int
Size[2] = { 1, 3 }, k = 0, number = 100;
// User enters the numbers
for
(
int
i = 0; i < 2; i++) {
int
* p = jagged[i];
for
(
int
j = 0; j < Size[k]; j++) {
*p = number++;
// move the pointer
p++;
}
k++;
}
k = 0;
// Display elements in Jagged array
for
(
int
i = 0; i < 2; i++) {
int
* p = jagged[i];
for
(
int
j = 0; j < Size[k]; j++) {
printf
(
"%d "
, *p);
// move the pointer to the next element
p++;
}
printf
(
"\n"
);
k++;
// move the pointer to the next row
jagged[i]++;
}
return
0;
}
Output:100 101 102 103
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