数字的字面表示：正负数、进位制、数学浮点数与科学计数法

示例：

/**
 *  @brief how about plain-number? show you here.
 *  @author wen`xuanpei
 *  @email 15873152445@163.com(query for any question here)
 */
#define _CRT_SECURE_NO_WARNINGS//support c-library in Microsoft-Visual-Studio
#include <stdio.h>

static void test_negative_positive_number(){
    printf("\n@%s begin:\n", __FUNCTION__);
    
    int neg = -10, pos = 20, pos2 = +20;
    printf("%d, %d, %d\n", neg, pos);

    float negF = -3.14, posF = 3.14, posF2 = +3.14;
    printf("%f, %f, %f\n", negF, posF);

    printf("\n@%s end:\n", __FUNCTION__);
}

static void print_integer_bits(int n){
    !n ? fputs("0b0", stdout) : ({print_integer_bits( ((unsigned int)n)>>1 ); putchar('0' + (n & 1) );});
}
static void test_number_carry(){
    printf("\n@%s begin:\n", __FUNCTION__);
    int numBin = 0b1101;//0B1101//[01]
    int numOtc = 012345670;//[0-7]
    int numDec = 1234567890;//[0-9]
    int numHex = 0x1234abcd;//0X12345678//[0-9a-fA-F]
    print_integer_bits(numBin);
    printf(", %o, %d, %x"/*  %X  */"\n"
    , numOtc, numDec, numHex    );
    printf("\n@%s end:\n", __FUNCTION__);
}

static void test_float_math_scientific_notation(){
    printf("\n@%s begin:\n", __FUNCTION__);
    float numMath = 3.14;//math notation
    float numSN1  = 3.14e3;//scientific notation
    float numSN2  = 3.14e+3;//scientific notation
    float numSN3  = 3.14e-3;//scientific notation
    printf("%f\n", numMath);
    printf("%f, %f, %f\n", numSN1, numSN2, numSN3);
    printf("\n@%s end:\n", __FUNCTION__);
}

int main(){
    test_negative_positive_number();
    test_number_carry();
    test_float_math_scientific_notation();
    getchar();
    return 0;
}

1）编译运行