算法--计算两个绝对路径之间的相对路径

#include<stdio.h>
#include<stdlib.h>

int CalculateSperatorNum(const char* str)
{
int count=0;
for(; *str; str++)
{
if(*str=='/')
count++;
}
return count;
}

void RelativePath(const char* strA, const char* strB, char*& result)
{
if(NULL==strA || NULL==strB)
return;

int sepA=CalculateSperatorNum(strA);
int sepB=CalculateSperatorNum(strB);

const char* ptrA=strA;
const char* ptrB=strB;
const char *p1=NULL, *p2=NULL;

while((*ptrA==*ptrB) && *ptrA!='\0') {ptrA++; ptrB++;}
if(*ptrA=='\0') return;
if(sepA>sepB){ p1=ptrA; p2=ptrB;}
else{ p2=ptrA; p1=ptrB;}

int n=CalculateSperatorNum(p1);
const char* p=p2;

int len=0;
while(*p++!='\0') len++;
result=(char*)malloc(sizeof(char)*(n*3+len+1));

int i=0;
for(i=0; i<n*3; i+=3)
{
*(result+i)='.';
*(result+i+1)='.';
*(result+i+2)='/';
}
while(*p2!='\0')
{
*(result+i++)=*p2;
p2++;
}
*(result+i)='\0';
}

int main(int argc, char** argv)
{
char* a="/qihoo/app/1/2/jtest.c", *b="/qihoo/app/a/b/c/d/df/fa/new.c";
char* r=NULL;
RelativePath(a, b, r);
printf("%s\n", r);

free(r);
return 0;
}