这里面的FP_SINGLE是什么意思？
#include <stdio.h>
#include <stdlib.h>

//浮点数结构体
typedef struct {
unsigned int nMant : 23; //尾数部分
unsigned int nExp : 8; //指数部分
unsigned int nSign : 1; //符号位
} FP_SINGLE;

int main()
{
char strBin[33] = { 0 };
float f = 19.625;
FP_SINGLE *p = (FP_SINGLE*)&f;

itoa(p->nSign, strBin, 2);
printf("sign: %s\n", strBin);
itoa(p->nExp, strBin, 2);
printf("exp: %s\n", strBin);
itoa(p->nMant, strBin, 2);
printf("mant: %s\n", strBin);

return 0;
}