C Pointers To Consts

pointers_to_constants.c

    /* ====================================================================== */
    /* Pointers & consts */
    /* ====================================================================== */

    /* POINTERS TO CONSTS */

    long value = 9999L;
    long value2 = 1111L;
    // only the value of what the pointer is pointing to is a constant
    // we can still change the reference of what the pointer is pointing to
    const long *pvalue = &value;
    // *pvalue = 1L; // throws error
    value = 1L; // OK
    printf("value: %d\n", value);

    // change the address of pvalue
    pvalue = &value2;
    printf("pvalue = %d\n\n\n", *pvalue);

    /* CONSTANT POINTERS */

    int count = 43;
    int count2 = 44;
    // after assignment, pcount cannot change the address it points to
    int *const pcount = &count;
    // pcount = &count2; // throws error
    *pcount = count2; // we can change the value
    printf("pcount = %d\n", *pcount); // 44
    printf("count = %d\n", count); // 44