1、使用额外的数组

#include <stdio.h>

void mergeArrays(int arr1[], int size1, int arr2[], int size2, int mergedArr[]) {
    int i, j, k;
    
    // 将第一个数组复制到合并后的数组
    for (i = 0; i < size1; i++) {
        mergedArr[i] = arr1[i];
    }
    
    // 将第二个数组追加到合并后的数组
    for (j = 0, k = size1; j < size2; j++, k++) {
        mergedArr[k] = arr2[j];
    }
}

int main() {
    int arr1[] = {1, 2, 3, 4, 5};
    int arr2[] = {6, 7, 8, 9, 10};
    int size1 = sizeof(arr1) / sizeof(arr1[0]);
    int size2 = sizeof(arr2) / sizeof(arr2[0]);
    int mergedArr[size1 + size2];
    
    mergeArrays(arr1, size1, arr2, size2, mergedArr);
    
    printf("Merged Array: ");
    for (int i = 0; i < size1 + size2; i++) {
        printf("%d ", mergedArr[i]);
    }
    
    return 0;
}

2、使用指针

#include <stdio.h>

void mergeArrays(int arr1[], int size1, int arr2[], int size2, int mergedArr[]) {
    int *pMergedArr = mergedArr;
    int *pEnd1 = arr1 + size1;
    int *pEnd2 = arr2 + size2;

    while (arr1 < pEnd1) {
        *pMergedArr++ = *arr1++;
    }
    while (arr2 < pEnd2) {
        *pMergedArr++ = *arr2++;
    }
}

int main() {
    int arr1[] = {1, 2, 3, 4, 5};
    int arr2[] = {6, 7, 8, 9, 10};
    int size1 = sizeof(arr1) / sizeof(arr1[0]);
    int size2 = sizeof(arr2) / sizeof(arr2[0]);
    int mergedArr[size1 + size2];
    
    mergeArrays(arr1, size1, arr2, size2, mergedArr);
    
    printf("Merged Array: ");
    for (int i = 0; i < size1 + size2; i++) {
        printf("%d ", mergedArr[i]);
    }
    
    return 0;
}

3、使用memcpy函数

#include <stdio.h>
#include <string.h>

void mergeArrays(int arr1[], int size1, int arr2[], int size2, int mergedArr[]) {
    memcpy(mergedArr, arr1, size1 * sizeof(int));
    memcpy(mergedArr + size1, arr2, size2 * sizeof(int));
}

int main() {
    int arr1[] = {1, 2, 3, 4, 5};
    int arr2[] = {6, 7, 8, 9, 10};
    int size1 = sizeof(arr1) / sizeof(arr1[0]);
    int size2 = sizeof(arr2) / sizeof(arr2[0]);
    int mergedArr[size1 + size2];
    
    mergeArrays(arr1, size1, arr2, size2, mergedArr);
    
    printf("Merged Array: ");
    for (int i = 0; i < size1 + size2; i++) {
        printf("%d ", mergedArr[i]);
    }
    
    return 0;
}

4、使用realloc动态分配内存

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

int* mergeArrays(int arr1[], int size1, int arr2[], int size2) {
    int *mergedArr = (int *)malloc((size1 + size2) * sizeof(int));
    
    if (mergedArr == NULL) {
        fprintf(stderr, "Memory allocation failed.\n");
        exit(1);
    }
    
    for (int i = 0; i < size1; i++) {
        mergedArr[i] = arr1[i];
    }
    
    for (int i = 0; i < size2; i++) {
        mergedArr[size1 + i] = arr2[i];
    }
    
    return mergedArr;
}

int main() {
    int arr1[] = {1, 2, 3, 4, 5};
    int arr2[] = {6, 7, 8, 9, 10};
    int size1 = sizeof(arr1) / sizeof(arr1[0]);
    int size2 = sizeof(arr2) / sizeof(arr2[0]);
    
    int *mergedArr = mergeArrays(arr1, size1, arr2, size2);
    
    printf("Merged Array: ");
    for (int i = 0; i < size1 + size2; i++) {
        printf("%d ", mergedArr[i]);
    }
    
    // Remember to free allocated memory
    free(mergedArr);
    
    return 0;
}

5、直接在原数组上合并

#include <stdio.h>

void mergeArrays(int arr1[], int *size1, int arr2[], int size2) {
    for (int i = 0; i < size2; i++) {
        arr1[*size1 + i] = arr2[i];
    }
    *size1 += size2;
}

int main() {
    int arr1[10] = {1, 2, 3, 4, 5};
    int arr2[] = {6, 7, 8, 9, 10};
    int size1 = 5;
    int size2 = sizeof(arr2) / sizeof(arr2[0]);
    
    mergeArrays(arr1, &size1, arr2, size2);
    
    printf("Merged Array: ");
    for (int i = 0; i < size1; i++) {
        printf("%d ", arr1[i]);
    }
    
    return 0;
}