C语言中整数与浮点数的内存存储区别解析

#include <stdio.h>
void print_binary(int num) {
    for (int i = 31; i >= 0; i--) {
        printf("%d", (num >> i) & 1);
        if (i % 8 == 0) printf(" ");
    }
    printf("\n");
}
int main() {
    int positive = 10;    // 正整数
    int negative = -10;   // 负整数
    printf("正数 %d 的二进制表示: ", positive);
    print_binary(positive);
    printf("负数 %d 的二进制表示: ", negative);
    print_binary(negative);
    return 0;
}

#include <stdio.h>
int main() {
    char a = 5;      // 00000101
    char b = -3;     // 11111101 (补码)
    char result = a + b;
    printf("%d + %d = %d\n", a, b, result);  // 输出: 5 + (-3) = 2
    // 验证溢出
    char max = 127;   // 01111111
    char min = -128;  // 10000000
    printf("127 + 1 = %d\n", max + 1);    // 输出: -128 (溢出)
    printf("-128 - 1 = %d\n", min - 1);   // 输出: 127 (溢出)
    return 0;
}

31       30-23     22-0
符号位   指数位     尾数位
S(1位)   E(8位)    M(23位)

#include <stdio.h>
#include <stdint.h>
void print_float_binary(float f) {
    uint32_t* p = (uint32_t*)&f;
    printf("浮点数 %.2f 的二进制表示:\n", f);
    printf("符号位: %d\n", (*p >> 31) & 1);
    printf("指数位: ");
    for (int i = 30; i >= 23; i--) {
        printf("%d", (*p >> i) & 1);
    }
    printf("\n尾数位: ");
    for (int i = 22; i >= 0; i--) {
        printf("%d", (*p >> i) & 1);
    }
    printf("\n\n");
}
int main() {
    float f1 = 10.5f;
    float f2 = -3.75f;
    float f3 = 0.1f;
    print_float_binary(f1);
    print_float_binary(f2);
    print_float_binary(f3);
    return 0;
}

#include <stdio.h>
#include <stdint.h>
void print_double_binary(double d) {
    uint64_t* p = (uint64_t*)&d;
    printf("双精度 %.2f 的二进制表示:\n", d);
    printf("符号位: %d\n", (*p >> 63) & 1);
    printf("指数位: ");
    for (int i = 62; i >= 52; i--) {
        printf("%d", (*p >> i) & 1);
    }
    printf("\n尾数位: ");
    for (int i = 51; i >= 0; i--) {
        printf("%d", (*p >> i) & 1);
    }
    printf("\n\n");
}
int main() {
    double d1 = 10.5;
    double d2 = 0.1;
    print_double_binary(d1);
    print_double_binary(d2);
    return 0;
}

#include <stdio.h>
#include <math.h>
int main() {
    float zero = 0.0f;
    float inf = 1.0f / zero;      // 无穷大
    float neg_inf = -1.0f / zero; // 负无穷大
    float nan = zero / zero;      // NaN
    printf("零: %f\n", zero);
    printf("无穷大: %f\n", inf);
    printf("负无穷大: %f\n", neg_inf);
    printf("NaN: %f\n", nan);
    // 检查特殊值
    printf("isinf(inf): %d\n", isinf(inf));
    printf("isnan(nan): %d\n", isnan(nan));
    return 0;
}

#include <stdio.h>
int main() {
    float a = 0.1f;
    float b = 0.2f;
    float c = 0.3f;
    printf("0.1 + 0.2 == 0.3 ? %s\n", (a + b == c) ? "true" : "false");
    printf("0.1 + 0.2 = %.20f\n", a + b);
    printf("0.3 = %.20f\n", c);
    // 正确的浮点数比较方法
    #define EPSILON 1e-6
    printf使用EPSILON比较: %s\n", 
           (fabs(a + b - c) < EPSILON) ? "true" : "false");
    return 0;
}

#include <stdio.h>
int check_endian() {
    int num = 1;
    char* p = (char*)&num;
    return *p;  // 返回1为小端，0为大端
}
int main() {
    int num = 0x12345678;
    char* p = (char*)&num;
    printf("系统字节序: %s\n", check_endian() ? "小端" : "大端");
    printf("数值 0x%x 在内存中的存储:\n", num);
    for (int i = 0; i < sizeof(int); i++) {
        printf("地址 %p: 0x%02x\n", p + i, (unsigned char)*(p + i));
    }
    return 0;
}

#include <stdio.h>
int main() {
    // 整数与浮点数转换
    int big_int = 123456789;
    float f = big_int;
    int converted_back = f;
    printf("原始整数: %d\n", big_int);
    printf("转换为浮点数: %.2f\n", f);
    printf("转换回整数: %d\n", converted_back);
    printf("精度损失: %d\n", big_int - converted_back);
    // 符号扩展问题
    char negative_char = -10;
    unsigned int unsigned_int = negative_char;
    printf("\n有符号char: %d\n", negative_char);
    printf("无符号int: %u\n", unsigned_int);  // 注意符号扩展
    return 0;
}

#include <stdio.h>
#include <stdint.h>
void print_memory(const void* ptr, size_t size) {
    const unsigned char* p = (const unsigned char*)ptr;
    printf("内存内容 (%zu 字节): ", size);
    for (size_t i = 0; i < size; i++) {
        printf("%02x ", p[i]);
    }
    printf("\n");
}
int main() {
    int integer = 0x12345678;
    float floating = 10.5f;
    double double_val = 3.1415926535;
    print_memory(&integer, sizeof(integer));
    print_memory(&floating, sizeof(floating));
    print_memory(&double_val, sizeof(double_val));
    return 0;
}