substring from string without using any standard api

#include "stdafx.h"
#include<stdio.h>
#include<string.h>
#include<iostream.h>

int compareposition(char* str1,char str2);
int main()
{
    char SensexGraphUrl[100];
	memset(SensexGraphUrl,0,100);
	int i,j;
	char* strarray="SENSEXGRAPHURL";
	char* str1= "SE";
    int count=0;
	int iLen = strlen(strarray);
	int iLen1 = strlen(str1) ;

	int pos=0;

	for(i=0;i<iLen1;i++)
	{
		pos = compareposition(strarray,str1[i]);
		cout<<"Pos"<<pos <<endl;
		//strncpy((char*)strarray[pos],"",1);
			
		if(iLen1 == 2)
		{
		
		pos = compareposition(strarray,str1[i]);
		cout<<"Pos"<<pos <<endl;
		}
	}
return 0;
}


int compareposition(char* str1,char str2)
{

	int j;

	int istrlen = strlen(str1); 
    
	for(j=0;j<istrlen;j++)
	{
		if(str1[j] == str2)
			return j;
		else
			continue;

	}


	return 0;
}