#include <cstdio>
#include <cstdlib>
#include <cstring>

const char * DELIMETER = " ";

int main(void)
{
	char pszInput[] = "1 2 3 10 11 12 13 19 199 200 201 202 300 305 499";

	char * token = strtok(pszInput, DELIMETER);

	bool bFirstNumber = true;		// for check ',' print
	bool bContinue = false;			// for check continuous
	int nLastNumber = -10;			// Should not continue the first input

	while( NULL != token )
	{
		int nCurrentNumber = atoi(token);

		if( (nLastNumber + 1) == nCurrentNumber )
		{
			// continuous number
			bContinue = true;
		}
		else
		{
			if( bContinue )
			{
				// print last
				printf("-%d", nLastNumber);

				bContinue = false;
			}

			if( bFirstNumber )
			{
				printf("%d", nCurrentNumber);
				bFirstNumber = false;
			}
			else
				printf(",%d", nCurrentNumber);

		}

		nLastNumber = nCurrentNumber;
		
		token = strtok( NULL, DELIMETER );
	}

	printf(".");

	return 0;
}

1-3,10-13,19,199-202,300,305,499.