c++ 实现部分string.h函数

#include <iostream>
using namespace std;

void Strcpy(char* ch1,const char* chSource) 
{
	int i = 0;
	while (chSource[i] != '\0') 
	{
		ch1[i] = chSource[i];
		i++;
	}
	ch1[i] = chSource[i];
}

int Strcmp(const char* ch1, const char* ch2) 
{
	int i = 0;
	int j = 0;
	int r = 0;                                            //The default value is equals.
	do 
	{
		if (ch1[i] > ch2[j]) 
		{
			r = 1;
			break;
		}
		if (ch1[i] < ch2[j]) 
		{
			r = -1;
			break;
		}
		i++;
		j++;
	} while (ch1[i] != '0' && ch2[j] != '0');
	return r;
}

void Strcat(char* destination, const char* source) 
{
	int i = 0;
	while (destination[i] != '\0') 
	{
		i++;
	}
	int j = 0;
	while (source[j] != '\0') 
	{
		destination[i] = source[j];
		i++;
		j++;
	}
	destination[i] = '\0';
}

int Strfnd(const char* child, const char* parent) 
{
	int r = -1;
	for (int i = 0; parent[i] != '\0'; i++) 
	{
		bool flag = true;
		for (int j = 0; child[j] != '\0'; j++) 
		{
			if (child[j] != parent[i + j])
			{
				flag = false;
				break;
			}
		}
		if (flag) 
		{
			r = i;
			break;
		};
	}
	return r;
}

int main()
{
	cout << Strfnd("123", "35134613451234134") << endl;
	cout << Strfnd("123", "351346134512234134") << endl;
	system("pause");
}