I'm trying to control the number of Digits i add in a String , but I couldn't control it since i am printing an Array of Strings .
float loads[n] = { 1,2,3,0.05,1,2,3,0.5,1,2,3,3,1,2 };
string print[nBits] = { "" };
int n=14;
int BB;
.
.
.
void main(){
for (int j = 0; j < nBits; ++j)// 2^n
{
for (int i = 0; i < n; ++i) // n
{
BB = arr[j][i];
R = loads[i];
if (BB == 1) {
print[j]+="" +std::to_string(loads[i])+"//";
}
}
}
But i eventually get an Array of strings that Looks like this :
0.050000//3.000000//...
Is there any way to control the Precision of the floating number before adding it to the String ?
(so i can have a resulting string control a fixed number of Digits instead)
0.05//3.00// ...
Use std::stringstream
together with std::fixed
and std::setprecision(n)
.
You can use the standard streaming mechanic:
You can use ostream to generate the string:
#include <ostream>
#include <sstream>
#include <iomanip>
std::ostringstream stream;
for(...) {
stream << loads[i] << "//";
}
std::string str = stream.str();
The idea is to generate a stream that you can stream strings too. You can then generate a std::string
out of it, using stream.str()
. Streams have default values for how to convert numbers. You can influence this with std::setprecision
and std::fixed
as well as other variables (for more info, see the C++ stdlib reference ).
Using std::setprecision
and std::fixed
.
std::ostringstream stream;
// set the precision of the stream to 2 and say we want fixed decimals, not
// scientific or other representations.
stream << std::setprecision(2) << std::fixed;
for(...) {
stream << loads[i] << "//";
}
std::string str = stream.str();
You find another example here .
You can always go the C way and use sprintf
although it's discouraged as you have to provide a buffer of correct length, eg:
char buf[50];
if (snprintf(buf, 50, "%.2f", loads[i]) > 0) {
std::string s(buf);
}
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