我的C/C++库理解之memchr

#include <cstdio>#include <cstring>//原型//void *memchr(const void *str, int c, size_t n)// 搜索参数str指向的字符串的前n个字节中第一次出现的字符c（unsigned char类型）。void  *Alex_memchr(const void *str, int c, size_t n);int main(){const char str[] = "Alex is cool!";char *ret = NULL;//ret = (char*)memchr(str, 'i', strlen(str));ret = (char*)Alex_memchr(str, 'i', strlen(str));printf("ret: %c\n", *ret);printf("ret: %s\n", ret);return 0;}void  *Alex_memchr(const void *str, int c, size_t n){while(n && (*((unsigned char*)str) != (unsigned char) c)){str = (unsigned char*)str + 1;--n;}return n?(void*)str:NULL;}