C语言中memcpy 的使用示例详解

void *memcpy(void *dest, const void *src, size_t n);

#include <stdio.h>
#include <string.h>
int main() {
    int src[] = {10, 20, 30, 40, 50};
    int dest[5];
    // 复制 5 个整数（每个 int 通常是 4 字节，共 20 字节）
    memcpy(dest, src, sizeof(src));
    for (int i = 0; i < 5; i++) {
        printf("%d ", dest[i]);  // 输出: 10 20 30 40 50
    }
    return 0;
}

#include <stdio.h>
#include <string.h>
typedef struct {
    int id;
    char name[20];
    float score;
} Student;
int main() {
    Student s1 = {1001, "Alice", 95.5f};
    Student s2;
    memcpy(&s2, &s1, sizeof(Student));
    printf("ID: %d, Name: %s, Score: %.1f\n", 
           s2.id, s2.name, s2.score);
    // 输出: ID: 1001, Name: Alice, Score: 95.5
    return 0;
}

#include <stdio.h>
#include <string.h>
int main() {
    char src[] = "Hello, world!";
    char dest[50];
    memcpy(dest, src, strlen(src) + 1);  // +1 包含 '\0'
    printf("Copied string: %s\n", dest);
    return 0;
}

char buf[] = "abcdef";
memmove(buf + 1, buf, 5);  // 将 "abcde" 左移一位
// 结果: "aabcde"

double data[100];
double subset[10];
// 只复制前 10 个 double
memcpy(subset, data, 10 * sizeof(double));