multiplication error using long variable

i have variable greater 32,767 can't use int type. instead use long, strange error when multiplying long variable.

for example, variable called 'product' , @ point set product = 1087 * 44. expect product = 47828 instead product =-17708!

what going on here?

here sample code shows problem i'm encountering:

code: [select]


long product = 0;

void setup(){
    serial.begin(9600);
}

void loop(){
    product = 1087*44; //this should return 47828 instead returns -17708
    serial.print("1087 * 44 = ");
    serial.println(product);
    delay(5000);
}


if way correct result however:

code: [select]


long product = 0;

void setup(){
    serial.begin(9600);
}

void loop(){
    product = 1087;
    serial.print(product);
    serial.print(" * ");
    serial.print(44);
    product=product*44;
    serial.print(" = ");
    serial.println(product);
    delay(5000);
}


am using incorrect syntax when write product=1087*44; ?

the problem both 1087 , 44 integers, multiplication done integers (which go 32,767), result (-17708) stored in long.  to around this, can declare integer constants longs appending l, e.g.:

code: [select]

product = 1087l * 44l;

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