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/************************Find sub-string**********************/
#include "stdio.h"
#include "conio.h"
#include "string.h"


int findsubstr(const char *str, char *sub);

void main()
{
char str[] = "ngoton.it blog for developer";
char sub1[] = "blog";
char sub2[] = "dev";
char sub3[] = "blog for developer";
char sub4[] = ".";
printf("str = '%s'\n", str);
printf("'%s' at %d\n", sub1, findsubstr(str, sub1));
printf("'%s' at %d\n", sub2, findsubstr(str, sub2));
printf("'%s' at %d\n", sub3, findsubstr(str, sub3));
printf("'%s' at %d\n", sub4, findsubstr(str, sub4));
getch();
}

/************************************************
Find sub-string in string
Return: -1 if not found
x (starting point in string) if found
*************************************************/
int findsubstr(const char *str, char *sub)
{
const char *p = str;
int len = strlen(sub);
while(*p != NULL)
{
if (strlen(p) >= len)
{
if (strncmp(p, sub, strlen(sub)) == 0)
{
return (p - str);
}
}
else
{
break;
}
p++;
}
return -1;
}