CODEWITHSUNDEEP
c++cgcc
Simd
Simd

Reputation: 21263

Is it possible to use C++'s sort in C?

I am writing C code but have to do a lot of calls to qsort which is taking most of the time. I notice that C++'s sort is faster than qsort. Is it possible for me to use it somehow? Here is a MWE in C:

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <stdint.h>

int cmpfunc (const void * a, const void * b) {
   return ( *(int*)a - *(int*)b );
}

int main(void) {
    int sz;
    srand(time(NULL));
    printf("Enter the size of array::");
    scanf("%d",&sz);
    uint32_t *arr = malloc(sz * sizeof *arr);
    int i;
    for(i=0;i<sz;i++)
        arr[i]=rand(); 
    clock_t begin = clock();
    qsort(arr, sz, sizeof *arr, cmpfunc);
    clock_t end = clock();
    double time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
    printf("%f seconds\n", time_spent);
    printf("%d\n", arr[10]);
   return 0;
}

Upvotes: 0

Views: 127

Answers (1)

Aykhan Hagverdili
Aykhan Hagverdili

Reputation: 29985

Yes, it is possible. C++ is designed to handle such things without much hassle. You need to compile the C++ function separately and then link it to your project:

The header should be valid C and C++. You need to use extern "C" by checking if it's C++:

// i32sort.h

#pragma once

#include <stdint.h>
#include <stddef.h>

#ifdef __cplusplus
extern "C" 
#endif // __cplusplus
void i32sort(int32_t*, size_t);

The source file is straight C++:

// i32sort.cpp

#include "i32sort.h"
#include <algorithm>

extern "C" void i32sort(int32_t* const data, size_t const size)
{
    std::sort(data, data + size);
}

Then compile it without linking:

$ clang++ -c i32sort.cpp -O3 -Wall -Wextra

Then include the i32sort.h header in your source file as usual:

// main.c

#include <stdio.h>
#include "i32sort.h"

int main(void)
{
    int32_t arr[] = { 5, 4, 3, 2, 1 };
    size_t const sz = sizeof (arr) / sizeof (* arr);
    i32sort(arr, sz);
    for (size_t i = 0; i < sz; ++i)
        printf("%d ", (int) arr[i]);
    putchar('\n');
}

While compiling your program, link it with the object file you generated previously:

$ clang main.c i32sort.o -O3 -Wall -Wextra
$ ./a
1 2 3 4 5

Upvotes: 5

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