How Can We Implement Jagged Arrays in C/C ?

Understanding Jagged Arrays in C/C

While the concept of jagged arrays, where rows can have varying lengths, is not directly supported in standard C/C , there are techniques to achieve similar functionality.

Upon attempting to declare a jagged array in C/C as shown below:

<code class="c++">int jagged[][] = { {0,1}, {1,2,3} };</code>

the compiler errors out, highlighting the requirement of specifying bounds for all dimensions except the first. To overcome this limitation, an alternative approach is utilizing an array of pointers.

Creating Jagged Arrays Using Array of Pointers

In C, a jagged array can be implemented using an array of pointers. Each element of this array points to a dynamically allocated subarray, where each subarray has its own varying length.

For example:

<code class="c">int *jagged[5];

// Assign memory to each subarray
jagged[0] = malloc(sizeof(int) * 10);
jagged[1] = malloc(sizeof(int) * 3);

// Accessing elements
*jagged[0] = 0;
*(jagged[0] + 1) = 1;

*jagged[1] = 1;
*(jagged[1] + 1) = 2;
*(jagged[1] + 2) = 3;

// Free memory after use
free(jagged[0]);
free(jagged[1]);</code>

This method allows for the creation of arrays with rows of varying sizes, simulating the behavior of a jagged array. It's important to note that the memory for each subarray must be dynamically allocated and manually freed to avoid memory leaks.

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