different result regarding order of precedence of operator in c

Question

I am complete new to c programming. i ran this code to try to understand the order of precedence in c programming-

#include <stdio.h>

int main()
{
    float sum = 8 / 4 * 2;

    printf("\n the solution of the expression is  %f", sum);
    return 0;
}

for this code i am correcly getting the output 4.000000

however if i write the print statement as

printf("\n the solution of the expression is  %f", 8 / 4 * 2);

i am getting the output as 0.000000. can anyone tell why does it give me different output for the same expression?

Raise the warning level of your compiler to the maximum and it should tell you. — the busybee, Aug 09 '22 at 10:30
If it were "precedence", you would expect "1.0000", not "0.00000"... You have to pay attention to what the results are telling you. — Fe2O3, Aug 09 '22 at 10:32

score 4 · Answer 1 · answered Aug 09 '22 at 10:25

The expression 8 / 4 * 2 is an integer operation with an integer result.

The variable sum if a float variable, so its value will be a floating point value, which can be used together with the %f format specifier.

But when you use the expression directly in printf you attempt to print an int value using the mismatching %f specifier, which leads to undefined behavior.

different result regarding order of precedence of operator in c

1 Answers1