import std.stdio;

int bruteForce(string containing, string str, int start = 0) {
	int matchStart = -1;
	int matchLen = 0;
	foreach(idx, ch; containing[start..$]) {
		if(str[matchLen] == ch) {
			matchStart = idx - matchLen + start;
			matchLen++;
			
			if(matchLen == str.length) {
				return matchStart;
			}
		} else {
			matchStart = -1;
			matchLen = 0;
		}
	}
	return -1;
}

typedef int function(string, string, int) SearchFunction;

void testSearch(string name, SearchFunction fn) {
	writefln("Testing search using %s algorithm", name);
	
	auto pp = "Programming Praxis";
	
	testSearchStr(fn, pp, pp, 0);
	testSearchStr(fn, pp, "Praxis", 12);
	testSearchStr(fn, pp, "Prax", 12);
	testSearchStr(fn, pp, "praxis", -1);
	testSearchStr(fn, pp, "P", 0);
	testSearchStr(fn, pp, "P", 12, 5);
}

void testSearchStr(SearchFunction fn, string containing, string str, int expected, int start = 0) {
	writefln("%s[%s] == %d [%d]", containing, str, expected, fn(containing, str, start));
	assert(fn(containing, str, start) == expected);
}

void main() {
	testSearch("brute force", &bruteForce);
}

Testing search using brute force algorithm
Programming Praxis[Programming Praxis] == 0 [0]
Programming Praxis[Praxis] == 12 [12]
Programming Praxis[Prax] == 12 [12]
Programming Praxis[praxis] == -1 [-1]
Programming Praxis[P] == 0 [0]
Programming Praxis[P] == 12 [12]