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;}