What is wrong in my calculation?

Question

What is output of this code?
union uTemp {
double a;
int b[10];
char c;
} u;
int main() {
printf("%d\n", sizeof(u));
}

Double 1*4=4
Int 10*2 =20
Char 1*1=1
Total--25
But the answer has 40. How??

Answer 1

int size is 4 so int 10 * 4 = 40

So union considered max value and max value is 40. That's why it is 40.

Note : Size of the union is the the size of its largest field because sufficient number of bytes must be reserved to store the largest sized field

Answer 2

Thank you 🅰🅹 🅐🅝🅐🅝🅣