Operators in C

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iso646.h>

int main(int argc, char* argv[]) {
    int x = 0;
    x or_eq 1;
    if (x >= 10 and x <= 20 or x > 0) {
        printf("Result is true\n");
    }
    return 0;
}