将双数组转换为unsigned short?
Prob = *((unsigned short*)(Prob)); Prob = (unsigned short)(Prob);
这对我不起作用。 如何正确转换?
您面临的最大问题是那些超过USHRT_MAX
双倍值。 其次,您需要解决四舍五入问题。 解决这两个问题并在.5
处设置舍入的简单方法看起来类似于以下函数array_dbl2short
返回成功转换为unsigned short
的double值的数量:
size_t array_dbl2short (unsigned short *usa, double *da, size_t n) { if (!usa || !da || !n) return 0; register size_t i, ncnvt = 0; for (i = 0; i < n; i++) { if (da[i] < 0 || (unsigned long long)(da[i] + 0.5) > USHRT_MAX) fprintf (stderr, "error: %lf outside range for conversion.\n", da[i]); else usa[ncnvt++] = (unsigned short)(da[i] + 0.5); } return ncnvt; }
它的一个简短例子是:
#include #include size_t array_dbl2short (unsigned short *usa, double *da, size_t n); int main (void) { double arr[] = { 1.49, 1.5, 65535.49, 65535.5, -1.9, 25671.8 }; size_t i, n, nelem = sizeof arr/sizeof *arr; unsigned short usarr[nelem]; if ((n = array_dbl2short (usarr, arr, nelem))) { printf ("\n unsigned short array:\n\n"); for (i = 0; i < n; i++) printf (" usarr[%zu] : %hu\n", i, usarr[i]); } return 0; } size_t array_dbl2short (unsigned short *usa, double *da, size_t n) { if (!usa || !da || !n) return 0; register size_t i, ncnvt = 0; for (i = 0; i < n; i++) { if (da[i] < 0 || (unsigned long long)(da[i] + 0.5) > USHRT_MAX) fprintf (stderr, "error: %lf outside range for conversion.\n", da[i]); else usa[ncnvt++] = (unsigned short)(da[i] + 0.5); } return ncnvt; }
( 注意: double
值的实部必须能够表示为unsigned long long
以使转换validation正常工作)
示例使用/输出
$ ./bin/dbl2ushort error: 65535.500000 outside range for conversion. error: -1.900000 outside range for conversion. unsigned short array: usarr[0] : 1 usarr[1] : 2 usarr[2] : 65535 usarr[3] : 25672
此解决方案未解决所有可能的舍入和转换问题。 您还可以使用math.h
的函数(例如modf
, round
等)来执行实部和舍入。 如果您还有其他问题,请与我们联系。
您需要显式转换每个值:
unsigned short * doubleToUShort(double * Prob_double, size_t N) { unsigned short * Prob = malloc(sizeof(unsigned short) * N); size_t i = 0; for (i = 0; i < N; i++) { Prob[i] = Prob_double[i]; } return Prob; }
这将趋向于零。 如果您想要舍入到最近,可以使用#include
并将该循环更改为
for (i = 0; i < N; i++) { Prob[i] = round(Prob_double[i]); }