C 語言冒泡排序同步調整姓名陣列：指針交換避免字串拷貝

問題

成績排序時，對應姓名也要同步交換。原碼用二維陣列 STR names[] 存姓名，交換需 strcpy 易越界且慢。

優化設計：指針陣列 + 雙陣列同步交換

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

#define MAX_N 256
#define NAME_LEN 32

int main() {
    int n;
    printf("人數: "); scanf("%d", &n); getchar();

    float *score = malloc(n * sizeof(float));
    char **name = malloc(n * sizeof(char*));
    for (int i = 0; i < n; i++) {
        name[i] = malloc(NAME_LEN);
        printf("姓名 %d: ", i+1); fgets(name[i], NAME_LEN, stdin);
        name[i][strcspn(name[i], "\n")] = 0; // 去換行
        printf("成績 %d: ", i+1); scanf("%f", &score[i]); getchar();
    }

    // 冒泡排序：同時交換 score 指標與 name 指標
    for (int i = 0; i < n-1; i++)
        for (int j = 0; j < n-1-i; j++)
            if (score[j] < score[j+1]) {
                float tmpS = score[j]; score[j] = score[j+1]; score[j+1] = tmpS;
                char *tmpN = name[j]; name[j] = name[j+1]; name[j+1] = tmpN;
            }

    printf("\n排序後:\n");
    for (int i = 0; i < n; i++)
        printf("%-10s %.1f\n", name[i], score[i]);

    // 釋放記憶體
    for (int i = 0; i < n; i++) free(name[i]);
    free(name); free(score);
    return 0;
}

關鍵改進

進階：結構體封裝

typedef struct { char name[NAME_LEN]; float score; } Student;
Student *arr = malloc(n * sizeof(Student));
// 排序時交換整個 Student 結構體 (memcpy 或直接賦值)

結構體法語意更清晰，現代編譯器優化後效能相當。