#include <stdio.h>
#include <string.h>
#include <stdlib.h>

/*add, subtract, multiply, divide*/
float add(int x, int y);
float sub(int x, int y);
float mul(int x, int y);
float divd(int x, int y);

int main( int argc, char *argv[]){

	/*VARIABLE DECLARATION BLOCK*/
	int num1,num2; /*first and second numbers*/
	long opr_loc; /*operator location*/
	int ctr,ctr2,argctr; /*for loop counters*/

	/*for output*/
	int a;
	int b;

	int d; /*desicion for operator*/
	/*1 = add
	  2 = subtract
	  3 = multiply
	  4 = divide */

	char *p; /*strchr pointer*/
	char *opr1;
	char *opr2;
	char *eq_in; /*input equation*/
	/*END VARIABLE DECLARATION BLOCK*/

	/*memory allocation*/
	eq_in = malloc(128*sizeof(char));
	opr1 = malloc(128*sizeof(char));
	opr2 = malloc(128*sizeof(char));

	/*EXPLANATION FOR THE FOLLOWING CODE:
	 * this for loop is used to allow spaces.
	 * by looping through the arguments
	 * I make 1 string with the equation in it
	 * (all of the argv in one string)*/
	for(argctr = 1; argctr < argc; argctr++)
	{
		if (strcmp(argv[argctr],"*")==0)
		{
			eq_in = strcat(eq_in,"*");
		}
		else
		{
			eq_in = strcat(eq_in,argv[argctr]);
		}
	}

	/*FIND OPERATOR*/
	if (strchr(eq_in,'+') != NULL)
	{
		p = strchr(eq_in,'+');
		d = 1;
	}

	else if(strchr(eq_in,'-') != NULL)
	{
		p = strchr(eq_in,'-');
		d = 2;
	}

	else if(strchr(eq_in,'*') != NULL)
	{
		p = strchr(eq_in, '*');
		d = 3;
	}

	else if(strchr(eq_in, '/') != NULL)
	{
		p = strchr(eq_in, '/');
		d = 4;
	}
	/*END FIND OPERATOR BLOCK*/


	/*SEPERATE OPERANDS FROM OPERATOR*/
	for(ctr = 0;ctr < (p-eq_in); ctr++)
	{
		opr1[ctr] = eq_in[ctr];
	}

	ctr2 = 0;
	for(ctr = p - eq_in + 1; ctr < strlen(eq_in); ctr++)
	{
		opr2[ctr2] = eq_in[ctr];/*USES FIRST COUNTER VARIABLE*/
		++ctr2;
	}

	/*ASCII TO INTEGER*/
	a = atoi(opr1);
	b = atoi(opr2);


	if(d == 1)
	{
		printf("%f\n",add(a,b));
	}

	else if(d == 2)
	{
		printf("%f\n",sub(a,b));
	}

	else if(d == 3)
	{
		printf("%f\n",mul(a,b));
	}

	else if(d == 4)
	{
		printf("%f\n",divd(a,b));
	}

	return 0;
}

float add(int x, int y)
{
	return x + y;
}

float sub(int x, int y)
{
	return x - y;
}

float mul(int x, int y)
{
	return x * y;
}

float divd(int x, int y)
{
	return x / y;
}