atol、isHuiwen、strcat、strcpy、strcmp

long atol(char* str){long result = 0;char tag;if (*str == '-'){tag = *str++;}while(*str >= '0' || *str <= '9'){result = 10 * result + (*str - 0);str++;}return (tag == '-')?(-result):result;}int isHuiwen(char* str){int len = strlen(str);for (int i = 0; i < len/2; i++){if (str[i] != str[len-i-1]){return 0;}}return 1;}char* strcat(char *strDest, const char *strSrc){char* address = strDest;//assert((strDest != NULL) && (strSrc != NULL));while (*strDest++);while (*strDest++ = *strSrc++);return address;}char* strcpy(char *strDest, const char *strSrc){char* address = strDest;//assert((strDest != NULL) && (strSrc != NULL));while (*strDest++ = *strSrc++);*strDest = '/0';return address;}int strcmp(const char *str1, const char *str2){while ((*str1 != NULL) && (*str2 != NULL) && (*str1 == *str2)){str1++;str2++;}return *str1 - *str2;}int fibonacci(int n){if (n == 1 || n == 2){return n;}return fibonacci(n-1) + fibonacci(n-2);}