小编noo*_*cpp的帖子

我有一堆整数,我把它放进去了stringstream.现在我想将stringstreams改为strings,同时保持s的恒定精度string.我该怎么办？我知道我可以使用stringstreams.precision(),但由于某些原因它不起作用:

float a = 5.23;
float b = 3.134;
float c = 3.0;

std::stringstream ta;
std::stringstream tb;
std::stringstream tc;

ta << a;
tb << b;
tc << c;

ta.precision(2);
tb.precision(2);
tc.precision(2);

std::string out = "";
out += ta.str() + "\n";
out += tb.str() + "\n";
out += tc.str() + "\n";

会回来5.23\n3.134\n3.0,而不是5.23\n3.13\n3.00