从字符串str中删除子字符串substr

int del_substr(char *str,char const *substr)
{
if(substr == NULL)
return 1;

char const *p=substr;
char *q=str;
char *g=str;
while (*q !='\0' && *p !='\0')
{
if(*q !=*p)
{
p=substr;
g=q;
q++;
}
else
{
p++;
q++;
}
}
if(*q=='\0' && *p!='\0')
return 0;
else
{
while (*q !='\0')
*(++g) = *q++;
*++g='\0';
return 1;
}
}