/*
    int および long long int の評価
    double および long double の評価
*/
#include <stdio.h>
#include <math.h>

/*
    int と long long int 型の乗算オーバーフローの確認
*/
void ev_int()
{
    int i;
    printf(" * size of int %d\n", sizeof(int));
    printf(" * range of int\n");
    i = 0xf0000000;
    do {
        i *= 2;
        printf("%d\n", i);
    } while (i < 0);

    long long int li;
    printf("\n * size of long long int %d\n", sizeof(long long int));
    printf(" * range of long long int\n");
    li = 0xf000000000000000LL;  /* LL, ULL */
    while (li != 0) {
        li *= 2;
        printf("%qd\n", li);    /* "Ld" do not work. "lld" works. */
    } while (li < 0LL);
    printf("\n");
}

/*
    double のふるまい

    !isnormal(d) do not work well.　原因未追究。
    see :  http://www.gnu.org/manual/glibc-2.2.5/html_node/Floating-Point-Classes.html#Floating%20Point%20Classes

*/
void ev_dbl()
{
    int i, c;
    double d, m;
    printf(" * size of double %d\n", sizeof(double));
    printf(" * large exponent of double\n");           /* 指数部が大きいとき */
    d = 8e307;
    m = exp(log(2.0) / 4);
    for (i = 0; i < 20; i += 1) {
        d *= m;
        c = __fpclassifyd(d);
        printf("%16.8g class %d\n", d, c);
        if (c != FP_NORMAL)
            break;
    }
    printf("\n");

    printf(" * small exponent of double (1)\n");       /* 指数部が小さいとき */
    d = 5e-308;
    m = exp(-log(2.0) / 4);
    for (i = 0; i < 20; i += 1) {
        d *= m;
        c = __fpclassifyd(d);
        printf("%16.8g class %d\n", d, c);
        if (c != FP_NORMAL)
            break;
    }
    printf("\n");

    printf(" * small exponent of double (2)\n");       /* 指数部が、もっと小さいとき */
    d = 5e-323;
    m = 0.5;
    for (i = 0; i < 20; i += 1) {
        d *= m;
        c = __fpclassifyd(d);
        printf("%16.8g class %d\n", d, c);
        if (c != FP_SUBNORMAL)
            break;
    }
    printf("\n");

    printf(" * mantissa precision of double\n");       /* 仮数部の精度 */
    d = 0.1;
    m = 10;
    for (i = 0; i < 40; i += 1) {
        d *= m;
        printf("%32.24e\n", d);
    }
    printf("\n");
}

/*
    long double のふるまい
*/
void ev_ldbl()
{
    int i;
    long double ld, lm;
    printf(" * size of long double %d\n", sizeof(long double));
    printf(" * mantissa precision of long double\n");  /* 仮数部の精度 */
    ld = 0.1;
    lm = 10;
    for (i = 0; i < 40; i += 1) {
        ld *= lm;
        printf("%32.24Le\n", ld);
    }
    printf("\n");

    printf(" * large exponent of long double\n");      /* 指数部が大きいとき */
    ld = 1e4929L;
    lm = 10;
    for (i = 0; i < 5; i += 1) {
        ld *= lm;
        printf("%16.8Le\n", ld);
    }
    printf("\n");

    printf(" * small exponent of long double\n");      /* 指数部が小さいとき */
    ld = 1e-4939L;
    lm = 1.0/10;
    for (i = 0; i < 15; i += 1) {
        ld *= lm;
        printf("%16.8Le\n", ld);
    }
    printf("\n");
}

int main(int argc, char* argv[])
{
    ev_int();
    ev_dbl();
    ev_ldbl();
    return 0;
}