31.第一个只出现一次的字符位置

*p != '\0'

*p != 0

#include "stdafx.h"
#include <string>
#include<iostream>
using namespace::std;
class Solution {
public:
	int FirstNotRepeatingChar(string str) {
		if (str.empty()) return -1;

		int arr[256] = { 0 };
		int length = str.length();
		for (int i = 0; i < length; i++){
			arr[(int)str[i]]++;
			std::cout << (int)str[i] << endl;
		}
		int retVal = 0;
		for (int i = 0; i < length; i++){
			if (arr[(int)str[i]] == 1)
				break;
			retVal++;
		}
		if (retVal == str.length()){
			retVal = -1;
		}
		return retVal;
	}
};
int _tmain(int argc, _TCHAR* argv[])
{
	Solution s;
	string test = "asdfasdfe";
	int result = s.FirstNotRepeatingChar(test);
	return 0;
}

#include "stdafx.h"
#include <string>
#include<iostream>
using namespace::std;
class Solution {
public:
	int FirstNotRepeatingChar(string str) {
		if (str.empty()) return -1;

		const char* p = str.data();
		int strLength = 0;
		int arr[256] = { 0 };
		while (*p != '\0'){
			arr[*p]++;
			p++;
			strLength++;
		}
		const char* p2 = str.c_str();
		int retVal = 0;
		while (*p2 != '\0'){
			if (arr[*p2] == 1)
				break;
			p2++; retVal++;
		}
		if (retVal == strLength){
			retVal = -1;
		}
		return retVal;
	}
};
int _tmain(int argc, _TCHAR* argv[])
{
	Solution s;
	string test = "asdfasdfe";
	int result = s.FirstNotRepeatingChar(test);
	return 0;
}

const char* p = str.data();

char* p = str.data();