帮我写一个归并排序的c语言代码

当然可以，以下是一个基于递归实现的归并排序的c语言代码:

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

void merge(int arr[], int left[], int leftLen, int right[], int rightLen) {
    int i, j, k;
    i = j = k = 0;

    while (i < leftLen && j < rightLen) {
        if (left[i] <= right[j]) {
            arr[k++] = left[i++];
        } else {
            arr[k++] = right[j++];
        }
    }

    while (i < leftLen) {
        arr[k++] = left[i++];
    }

    while (j < rightLen) {
        arr[k++] = right[j++];
    }
}

void mergeSort(int arr[], int arrLen) {
    if (arrLen < 2) {
        return;
    }

    int mid = arrLen / 2;
    int left[mid];
    int right[arrLen - mid];

    for (int i = 0; i < mid; i++) {
        left[i] = arr[i];
    }
    for (int i = mid; i < arrLen; i++) {
        right[i - mid] = arr[i];
    }

    mergeSort(left, mid);
    mergeSort(right, arrLen - mid);
    merge(arr, left, mid, right, arrLen - mid);
}

int main() {
    int arr[] = {4, 2, 1, 3, 6, 5, 7};
    int arrLen = sizeof(arr) / sizeof(int);

    printf("Original array: ");
    for (int i = 0; i < arrLen; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");

    mergeSort(arr, arrLen);

    printf("Sorted array: ");
    for (int i = 0; i < arrLen; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");

    return 0;
}

该代码实现了归并排序的主要逻辑，将一个无序数组按照大小顺序排列。如果您还有其他问题，欢迎随时提出。