C语言中的strncpy()函数的用法及应用场景详解

char *strncpy(char *dest, const char *src, size_t n);

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

int main() {
    char src[] = "Hello, World!";
    char dest[20];

    // 使用strncpy复制字符串
    strncpy(dest, src, sizeof(dest) - 1);
    dest[sizeof(dest) - 1] = '\0'; // 确保目标字符串以空字符结尾

    printf("Source: %s\n", src);
    printf("Destination: %s\n", dest);

    return 0;
}

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

int main() {
    char src[] = "Hello, World!";
    char dest[6];

    // 复制前5个字符
    strncpy(dest, src, 5);
    dest[5] = '\0'; // 手动添加空字符

    printf("Source: %s\n", src);
    printf("Partial Destination: %s\n", dest);

    return 0;
}

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

int main() {
    char src[] = "Hi";
    char dest[10];

    // 复制源字符串并添加空字符
    strncpy(dest, src, sizeof(dest));
    // 不需要手动添加空字符，因为strncpy会自动填充

    printf("Source: %s\n", src);
    printf("Destination: %s\n", dest);

    return 0;
}

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

void safeCopy(char *dest, const char *src, size_t destSize) {
    strncpy(dest, src, destSize - 1);
    dest[destSize - 1] = '\0';
}

int main() {
    char src[] = "This is a very long string that could overflow the buffer if not handled properly.";
    char dest[30];

    safeCopy(dest, src, sizeof(dest));

    printf("Source: %s\n", src);
    printf("Safe Copy: %s\n", dest);

    return 0;
}

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

typedef struct {
    char name[20];
    int age;
} Person;

void setName(Person *p, const char *name) {
    strncpy(p->name, name, sizeof(p->name) - 1);
    p->name[sizeof(p->name) - 1] = '\0';
}

int main() {
    Person p;
    setName(&p, "John Doe");

    printf("Name: %s\n", p.name);
    printf("Age: %d\n", p.age);

    return 0;
}

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

void truncateString(char *dest, const char *src, size_t maxLength) {
    strncpy(dest, src, maxLength);
    dest[maxLength] = '\0';
}

int main() {
    char src[] = "This is a long string that will be truncated.";
    char dest[20];

    truncateString(dest, src, sizeof(dest) - 1);

    printf("Source: %s\n", src);
    printf("Truncated: %s\n", dest);

    return 0;
}

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

int main() {
    char src[] = "Hello, World!";
    char dest[5];

    strncpy(dest, src, sizeof(dest) - 1);
    dest[sizeof(dest) - 1] = '\0'; // 确保目标字符串以空字符结尾

    printf("Source: %s\n", src);
    printf("Destination: %s\n", dest);

    return 0;
}

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

int main() {
    char src[] = "Hi";
    char dest[10];

    strncpy(dest, src, sizeof(dest));

    printf("Source: %s\n", src);
    printf("Destination: %s\n", dest);

    for (int i = 0; i < sizeof(dest); i++) {
        printf("%d ", dest[i]); // 输出字符的ASCII值
    }
    printf("\n");

    return 0;
}

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

void safeCopyUTF8(char *dest, const char *src, size_t destSize) {
    strncpy(dest, src, destSize - 1);
    dest[destSize - 1] = '\0';

    // 确保多字节字符的完整性
    size_t len = strlen(dest);
    while ((dest[len] & 0x80) && !(dest[len] & 0x40)) {
        dest[len--] = '\0';
    }
}

int main() {
    char src[] = "你好，世界！"; // "Hello, World!" in Chinese
    char dest[10];

    safeCopyUTF8(dest, src, sizeof(dest));

    printf("Source: %s\n", src);
    printf("UTF-8 Safe Copy: %s\n", dest);

    return 0;
}

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

void safeStrCat(char *dest, const char *src, size_t destSize) {
    size_t destLen = strlen(dest);
    if (destLen < destSize - 1) {
        strncat(dest, src, destSize - destLen - 1);
    }
}

int main() {
    char dest[20] = "Hello, ";
    char src[] = "World!";

    safeStrCat(dest, src, sizeof(dest));

    printf("Concatenated: %s\n", dest);

    return 0;
}