使用 sprintf_s 来转换，代码如下：
char buffer_max[
20], buffer_min[
20], buffer_ratio[
20];
sprintf_s(buffer_max,
"%f",
max[i]);
sprintf_s(buffer_min,
"%f",
min[j]);
sprintf_s(buffer_ratio,
"%f", ratio[r]);
string str_max = buffer_max;
string str_min = buffer_min;
string str_ration = buffer_ratio;
string bvh_output = CCommonFunction::GetTestDataDir() +
"/../work/NCSetKneeAngleDampStatus-" +
str_max +
"-"+ str_min+
"-" +str_ration +
".bvh";
