array length c

int a[20];
int length;
length = sizeof(a) / sizeof(int);
#include <stdio.h>
#include <string.h>
int main()
{
    char a[20]="Program";
    char b[20]={'P','r','o','g','r','a','m','\0'};

    // using the %zu format specifier to print size_t
    printf("Length of string a = %zu \n",strlen(a));
    printf("Length of string b = %zu \n",strlen(b));

    return 0;
}int prices[5] = { 1, 2, 3, 4, 5 };

int size = sizeof prices / sizeof prices[0];

printf("%u", size); /* 5 */int a[17];
size_t n = sizeof(a)/sizeof(a[0]);