题解 | #复制部分字符串#

//#include <iostream>
#include <bits/stdc++.h>
#include <stdio.h>
#include <string.h>
using namespace std;

int main() {

    char str[31] = { 0 };
    int m;
    cin >> str;
    //gets(str);//c++环境下，这个不能用
    int size_old = strlen(str) + 1;
    scanf("%d\n", &m);
    int size_new = size_old - (m - 1);

    /*初始化数组，使其每个元素都是'\0'，'\0'字符的ascii码就是0：https://blog.csdn.net/qq_32634545/article/details/75454017*/
    char str_new[31] = {0};//后面打印用到printf字符串，所以先把每个元素初始化位\0,否则最后一个printf的字符容易出现乱码

    /*用指针来实现*/
    char *str_ptr = str + m -1;
    char *str_new_ptr = str_new;
    while( *str_ptr != '\0'){
        *str_new_ptr = *str_ptr;
        str_new_ptr++;
        str_ptr++;
    }

    /*用数组来实现*/
    // for(int i = 0; i < size_new; i++){
    //     str_new[i] = str[i + m - 1];
    // }

    printf("%s", str_new);
    return 0;
}