C语言创建随机数数组并排序，调用排序函数的实现求助

Hey there! Let's walk through exactly how to create two random number arrays, sort them with a reusable function, and print the sorted results in main(). I'll break down each part to clear up the confusion around declaring arrays for function calls.

Step 1: Declare Your Arrays #

First, decide on the size of your arrays. Using a macro makes it easy to adjust the length later. In main(), you can declare fixed-size arrays directly on the stack like this:

#define ARRAY_SIZE 10  // Tweak this number to change how many elements your arrays hold

int main() {
    int arr1[ARRAY_SIZE];
    int arr2[ARRAY_SIZE];
    // ... rest of your code will go here
}

If you need dynamic sizes (like letting the user choose the length), you could use malloc() instead, but fixed-size works perfectly for this example.

Step 2: Generate Random Numbers #

To fill the arrays with random values, you'll need the <stdlib.h> and <time.h> headers. Use srand() to seed the random number generator (so you get different values every time you run the program), then loop through each array to assign random numbers:

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

// ... (macro and main declaration here)

// Initialize random seed with current time
srand(time(NULL));

// Fill arr1 with random numbers between 0 and 99
for (int i = 0; i < ARRAY_SIZE; i++) {
    arr1[i] = rand() % 100;
}

// Fill arr2 the same way
for (int i = 0; i < ARRAY_SIZE; i++) {
    arr2[i] = rand() % 100;
}

Step 3: Write a Reusable Sorting Function #

Here's the key part you were confused about: when passing an array to a function, C treats it as a pointer to the first element. You can declare the function parameter in two equivalent ways—they work exactly the same:

• void sortArray(int *arr, int size) (using pointer syntax)
• void sortArray(int arr[], int size) (using array syntax, which is just a friendly shortcut for the pointer version)

Let's implement a simple bubble sort (you could also use the standard library's qsort() if you prefer a more efficient option):

void sortArray(int arr[], int size) {
    for (int i = 0; i < size - 1; i++) {
        for (int j = 0; j < size - i - 1; j++) {
            if (arr[j] > arr[j + 1]) {
                // Swap the two elements
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

Important note: Since we're modifying the array through its pointer, the changes will affect the original array in main()—no need to return anything from the function!

Step 4: Call the Sort Function and Print Results #

Back in main(), call sortArray() on both arrays, then loop through each to print the sorted values:

// Sort both arrays
sortArray(arr1, ARRAY_SIZE);
sortArray(arr2, ARRAY_SIZE);

// Print sorted arr1
printf("Sorted Array 1:\n");
for (int i = 0; i < ARRAY_SIZE; i++) {
    printf("%d ", arr1[i]);
}
printf("\n");

// Print sorted arr2
printf("Sorted Array 2:\n");
for (int i = 0; i < ARRAY_SIZE; i++) {
    printf("%d ", arr2[i]);
}
printf("\n");

return 0;
}

Full Working Code #

Putting it all together, here's the complete program you can copy and run:

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

#define ARRAY_SIZE 10

void sortArray(int arr[], int size) {
    for (int i = 0; i < size - 1; i++) {
        for (int j = 0; j < size - i - 1; j++) {
            if (arr[j] > arr[j + 1]) {
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

int main() {
    int arr1[ARRAY_SIZE];
    int arr2[ARRAY_SIZE];

    // Seed random number generator with current time
    srand(time(NULL));

    // Fill both arrays with random numbers (0-99)
    for (int i = 0; i < ARRAY_SIZE; i++) {
        arr1[i] = rand() % 100;
        arr2[i] = rand() % 100;
    }

    // Sort the arrays
    sortArray(arr1, ARRAY_SIZE);
    sortArray(arr2, ARRAY_SIZE);

    // Print the sorted results
    printf("Sorted Array 1:\n");
    for (int i = 0; i < ARRAY_SIZE; i++) {
        printf("%d ", arr1[i]);
    }
    printf("\n\n");

    printf("Sorted Array 2:\n");
    for (int i = 0; i < ARRAY_SIZE; i++) {
        printf("%d ", arr2[i]);
    }
    printf("\n");

    return 0;
}

Quick Clarification on Array Parameters #

When you pass arr1 to sortArray(), you're actually passing a pointer to the first element of arr1. That's why both int arr[] and int *arr work as parameters—they're interchangeable here. The function can modify the original array because it's working directly with the memory location of the array elements.

内容的提问来源于stack exchange，提问作者Dušo Morháč