How to Efficiently Sort a Large Array of Structs in C?

When it comes to sorting a large array of structs based on a specific field in C, there are a few options to consider. One approach is to use a custom sorting function, while another is to utilize a standard library function like qsort. Let's explore both options and discuss some tips for optimizing the sorting process.

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For efficient sorting of a large array of structs in C, use the qsort function from the standard library along with a custom comparison function tailored to your struct's sorting criteria. Example:


#include <stdio.h>

#include <stdlib.h>

struct MyStruct {

    int id;

    // other fields...

};

int compareStructs(const void *a, const void *b) {

    return ((struct MyStruct*)a)->id - ((struct MyStruct*)b)->id;

}

int main() {

    struct MyStruct myArray[1000]; // adjust size as needed

    // initialize array...

    size_t arraySize = sizeof(myArray) / sizeof(myArray[0]);

    qsort(myArray, arraySize, sizeof(myArray[0]), compareStructs);

    // further processing...

    return 0;

}


This example uses the qsort function provided by the C standard library. The compareStructs function is a comparison function that compares elements of your struct based on a specific field (id in this case). You can modify the comparison function based on the field you want to use for sorting.

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