IEEE 浮点表示
我创建了以下程序来查找浮点数的位模式。但我得到了不同然后我计算：
#include<stdio.h>
int main(void){
float f = 1.234;
char *ch;
ch = (char *)(&f);
printf("\n%d\n", *ch);
ch++;
printf("\n%d\n", *ch);
ch++;
printf("\n%d\n", *ch);
ch++;
printf("\n%d\n", *ch);
// printf("%d %d %d %d", *ch, *(ch+1), *(ch+2), *(ch+3));
printf("\n%f %e", f, f);
return 0;
}
它给了我输出：
-74
-13
-99
63
1.234000 1.234000e+00
这意味着什么，因为我期望位模式为：
00111111 10111011 11100111 0110110
我错了，请纠正我
I have created following program to find the bit pattern of floating point no. but i got different then i calculated:
#include<stdio.h>
int main(void){
float f = 1.234;
char *ch;
ch = (char *)(&f);
printf("\n%d\n", *ch);
ch++;
printf("\n%d\n", *ch);
ch++;
printf("\n%d\n", *ch);
ch++;
printf("\n%d\n", *ch);
// printf("%d %d %d %d", *ch, *(ch+1), *(ch+2), *(ch+3));
printf("\n%f %e", f, f);
return 0;
}
It gives me output:
-74
-13
-99
63
1.234000 1.234000e+00
What does it mean because i was expecting bit pattern as:
00111111 10111011 11100111 0110110
where i am wrong please correct me
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评论（3）
我不确定你从哪里得到这个位模式。
对于 IEEE-754，
1.234相当于0x3F9DF3B6的底层表示（参见例如 http://babbage.cs.qc.edu/IEEE-754/Decimal.html）。所以我们有：根据您的系统字节顺序，您可能会发现这些字节以其他顺序出现。
I'm not sure where you got that bit pattern from.
For IEEE-754,
1.234is equivalent to an underlying representation of0x3F9DF3B6(see e.g. http://babbage.cs.qc.edu/IEEE-754/Decimal.html). So we have:Depending on your system endianness, you might find that these bytes come up in the other order.
标准 C 中没有内置二进制
printf格式。如果这是您想要的输出格式，您需要编写自己的格式。您可以通过使用%x查看十六进制输出来更接近；也许这会给你带来你需要的东西？There is no binary
printfformat built into standard C. You'll need to write your own if that's the output format you want. You could get closer by using%xto see hexadecimal output; maybe that will get you what you need?您期望的位模式是错误的，它应该是：
它产生的数字与您得到的数字完全相同。
符号、指数和有效值为：
0, 127, 1962934
The bit pattern that you expect is wrong, it should be:
which produces exactly the numbers you got.
The sign, exponent and significant are:
0, 127, 1962934