找出最大长度子字符串（只包含字母），打印并且返回长度.

/**
找出最大长度子字符串（只包含字母），打印并且返回长度。
例如str= "abc123abcd234abcdefgha324adsdawqdasdaseqqwe345abchded"
最大子字符串是“adsdawqdasdaseqqwe”
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int FindMaxSubString( char * str);
int FindMaxSubString( char * str)
{
	int maxStartIndex=0;
	int curStartIndex=0;
	int maxLength=0;
	int curLength=0;
	int findflag=0;
	unsigned int i=0;
    for(i=0;i<strlen(str);i++)
    {
    	if(str[i] >= 'a'&&str[i] <= 'z')
    	{
    		if(findflag==0)
    		{
    			findflag=1;
    			curLength=1;
    			curStartIndex=i;
    		}else
    		{
    			curLength++;
    		}
    	}
    	if(str[i]<'a'||str[i]>'z')
    	{
    		findflag=0;
    		if(curLength>maxLength)
    		{
    			maxLength=curLength;
    			maxStartIndex=curStartIndex;
    			curLength=0;
    		}
    	}

    }
   	char *p=NULL;
    p=&str[maxStartIndex];
    printf("Result = ");
    while(*p >= 'a'&&*p <= 'z')
    {
    	putchar(*p);
    	p++;
    }
    printf("\n");
    return maxLength;
}

void main(void)
{
	char *str="abc123abcd234abcdefgha324adsdawqdasdaseqqwe345abchded";
	int maxlenth=0;
	maxlenth=FindMaxSubString(str);
	printf("MaxSubString.Length=%d\n",maxlenth);
}