【字串】字串拷貝和長度

#include <iostream>#include <assert.h>using namespace std;//字串長度int strlen_bxy(const char *str){assert(str != NULL);int len = 0;while(*str++ != '\0'){++len;}return len;}//字串拷貝char *strcpy_bxy(char *to,const char *from){assert((to != NULL) && (from != NULL));char *result = to;while((*to++ = *from++) != '\0');return result;}//char *strncpy_bxy(char *to,const char *from,size_t count){assert((to != NULL) && (from != NULL));char *result = to;while(count--){if(*from != '\0'){*to++ = *from++;}else{*to++ = '\0';}}*to++ = '\0';return result;}void main(){const char *str = "bxybao@163.com";//測試strlen函數cout << strlen_bxy(str)<<endl;int length = strlen_bxy(str);char *copy = new char[length+1];strcpy_bxy(copy,str);cout << copy <<endl;char *ncopy = new char[7];strncpy_bxy(ncopy,str,6);cout << ncopy <<endl;}