模拟strcpy函数：可让用户自定义拷贝任意字符数的字符串

#include<stdio.h>
#define MAX 200

int main()
{
    char str1[MAX]; 
    char str2[MAX];
    int n;
    char *target1= str1;
    char *target2= str2;
    char ch;
    
    printf("请输入字符串：");
    fgets(str1,MAX,stdin);
    printf("\n");
    
    printf("请输入拷贝到第几个字符:");
    scanf("%d",&n);
    
    while(n--)
    {
        
        ch = *target2++ =*target1++;
        if(ch=='\0')
        {
            break;
        }
        if((int)ch<0)
        {
            *target2++ = *target1++;
        }
        
    }
    
    *target2='\0';
    
    printf("%s",str2);
    
    return 0;
}