char array in structs - why does strlen() return the correct value here?

Question

I have a simple program like this:

#include 
#include 
#include 

typedef struct 
{
    int numberOfDays;
             


        

Answer 1

When you partially initialise the struct, those parts not specifically initialised are set to 0.

So the strings do have a terminating 0 and so strlen() returns the correct value.

#include 
#include 

int main(){
int i;
    char s[10] = {'a', 'b', 'c'};
    for (i=0; i<10; i++)
        printf("%d ", s[i]);
    printf("\n%d\n", strlen(s));
    return 0;
}

Program output:

97 98 99 0 0 0 0 0 0 0
3