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Editorial Team
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Asked: 2026-05-20T10:41:29+00:00

I’m trying to compute this equation: int n = 89; int SUMx = 347762,

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I’m trying to compute this equation:

int n = 89;
int SUMx = 347762, SUMy = 4898, SUMxy = 19671265;
long long SUMxx = 1370329156;

printf("(float)(( SUMx*SUMy - n*SUMxy ) / ( SUMx*SUMx - n*SUMxx ) = %f \n", (float)(( SUMx*SUMy - n*SUMxy ) / ( SUMx*SUMx - n*SUMxx )));

SUMxx used to be int, but doing n*SUMxx overflowed, so I changed it to long long. Now it is just giving me an answer of 0.000000 where I want it to be 0.0464.

How do I accomplish this? Is there some discrepancy where I need to change the other datatypes to long long as well?

Thank you 🙂

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1 Answer

  1. Editorial Team

    You’re doing integer division so anything between 0 and 1 will be truncated before you cast it to float. Cast one of the values to double (or float) before doing the arithmetic so you’re using floating point arithmetic instead

    int n = 89;
int SUMx = 347762, SUMy = 4898, SUMxy = 19671265;
long long SUMxx = 1370329156;

printf("(float)(( SUMx*SUMy - n*SUMxy ) / ( SUMx*SUMx - n*SUMxx ) = %f \n",
       ( SUMx*SUMy - n*SUMxy ) / (float)( SUMx*SUMx - n*SUMxx ));
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