CODEWITHSUNDEEP
c
user2796222
user2796222

Reputation: 53

what is the difference in output for float values?

#include <stdio.h>

int main() {
    float a = 0.7;
    int c;
    c = a < 0.7;
    printf("%d", c);
}

Output printed is 1 though it is printing 0 for all cases except 0.7,7.7 and 0.9, why it is so??? Also it should be 0 because precedence of '<' operator is more than '=' operator

Upvotes: 2

Views: 146

Answers (2)

n. m. could be an AI
n. m. could be an AI

Reputation: 120239

0.7 cannot be represented exactly as a float value, so a stores some approximation of it. The gotcha here is that the literal 0.7 has type double, so a more precise approximation of 0.7 is used to represent it. That approximation may differ from the less precise one in either direction.

To fix, use a double variable, or a float literal 0.7f.

Upvotes: 13

Paul Evans
Paul Evans

Reputation: 27577

Your basically dealing with the fact that 0.1 is a repeating decimal in binary. So things that look nice and clean as literals (i.e. 0.7) can't be represented exactly. Coupled with this you're mixing types since the literal 0.7 is a double.

Upvotes: 0

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