数据结构之数组处理串函数

#include<iostream>
#include<cstdio>
#include<cstdlib>
using namespace std;
void StrConcat(char S[], char T[], char ST[])
{
	int i = 0, j = 0, k = 0;
	while (S[i])
		ST[k++] = S[i++];
	while (T[j])
		ST[k++] = T[j++];
	ST[k] = '\0';
	return;
}
int StrLen(char S[])
{
	int i = 0;
	while (S[i])
		i++;
	return i;
}
void StrCopy(char S[], char T[])
{
	int i = 0;
	while (T[i]){
		S[i] = T[i];
		++i;
	}
	S[i] = '\0';
	return;
}
bool StrEmpty(char S[])
{
	if (!S[0])
		return true;
	else
		return false;
}
void StrDestroy(char S[])
{
	delete S;
}
bool SubString(char Sub[], char S[], int pos, int len)
{
	int slen = StrLen(S); int i;
	if (pos<1 || pos>slen)
		return false;
	if (len<0 || len>slen - pos + 1)
		return false;
	for (i = 0; i < len; i++)
		Sub[i] = S[pos-1+i];
	Sub[i] = '\0';
	return true;
}
int StrIndex(char S[], char T[], int pos)
{
	int i = pos - 1; int j = 0;
	while (S[i] && T[j])
	{
		if (S[i] == T[j])
		{
			i++; j++;
		}
		else
		{
			i = i - j + 1; j = 0;
		}
	}
	if (j== StrLen(T))
		return i-j+1;
	else
		return 0;
}
int main(void)
{
	char S[20] = "zhangsanfeng";
	char T[5] = "san";
	char ST[30];
	char T1[5];
	cout << StrLen(S)<<endl;
	StrConcat(S, T, ST);
	cout << ST << endl;
	StrCopy(T1, T);
	cout << T1 << endl;
	int i = StrIndex(S, T, 7);
	cout << i << endl;
	return (0);
}