"Sizeof" and "strlen" find the difference between array length

1. sizeof(str) calculates the total size of the array in bytes

#include<stdio.h>
int main()
{
    
    
	char str[] = "hello CSDN";
	printf("%d\n", sizeof(str));
}

The output result is 11

2. Strlen is to find the length of the
string. Find the end of the string'\0', how many characters appear before the'\0', the length is

#include<stdio.h>
int main()
{
    
    
	char str[] = "hello CSDN";
	printf("%d\n", strlen(str));
}

The output result is 10