第一种:

#include<stdio.h>
#include<iostream>

void copy_string(char* p1, char* p2) {
    for (; *p1 != '\0'; *p1++,*p2++)
    {
        *p2 = *p1;
    }
    *p2 = '\0';
}

int main() {
    char* str1 = (char*) "hello world";
    char str2[] = "i am a student";
    copy_string(str1, str2);
    printf("%s\n",str2);
    system("pause");
    return 0;
}

第二种:

#include<stdio.h>
#include<iostream>

void copy_string(char* p1, char* p2) {
    while ((*p2 = *p1) != '\0')
    {
        *p2++;
        *p1++;
    }
}

int main() {
    char* str1 = (char*)"hello world";
    char str2[] = "i am a student";
    copy_string(str1, str2);
    printf("%s\n", str2);
    system("pause");
    return 0;
}

第三种:

#include<stdio.h>
#include<iostream>

void copy_string(char* p1, char* p2) {
    //指针运算符比++优先级高
    //也就是先将*p1的值给*p2,再进行++操作,i++是先赋值,后自增
    while ((*p2++ = *p1++) != '\0')
}

int main() {
    char* str1 = (char*)"hello world";
    char str2[] = "i am a student";
    copy_string(str1, str2);
    printf("%s\n", str2);
    system("pause");
    return 0;
}

第四种:

#include<stdio.h>
#include<iostream>

void copy_string(char* p1, char* p2) {
    while (*p1 != '\0') {
        *p2++ = *p1++;
    }
    *p2 = '\0';
}

int main() {
    char* str1 = (char*)"hello world";
    char str2[] = "i am a student";
    copy_string(str1, str2);
    printf("%s\n", str2);
    system("pause");
    return 0;
}

第五种:

#include<stdio.h>
#include<iostream>

void copy_string(char* p1, char* p2) {
    //当*p2++ = *p1++变为0时,就会结束循环
    while (*p2++ = *p1++) {
        ; //'\0' == 0;结束标志
    }
}

int main() {
    char* str1 = (char*)"hello world";
    char str2[] = "i am a student";
    copy_string(str1, str2);
    printf("%s\n", str2);
    system("pause");
    return 0;
}

第六种:

#include<stdio.h>
#include<iostream>

void copy_string(char* p1, char* p2) {
    for (; *p2++ = *p1++;) {
        ; //'\0' == 0;结束标志
    }
}

int main() {
    char* str1 = (char*)"hello world";
    char str2[] = "i am a student";
    copy_string(str1, str2);
    printf("%s\n", str2);
    system("pause");
    return 0;
}

第七种:

#include<stdio.h>
#include<iostream>

void copy_string(char str1[], char str2[]) {
    char* p1, * p2;
    p1 = str1;
    p2 = str2;
    while((*p2++ = *p1++)!='\0') {
        ; //'\0' == 0;结束标志
    }
}

int main() {
    char* str1 = (char*)"hello world";
    char str2[] = "i am a student";
    copy_string(str1, str2);
    printf("%s\n", str2);
    system("pause");
    return 0;
}
12-18 18:25