I don't quite understand the purpose of showpoint, i know it forces to show a decimal point, but having "cout << setprecision << fixed" is enough without the use of showpoint.
Can you show me an example where showpoint is a must have?
When covering a large range of values it may be desirable to have the formatting logic to switch between the use of fixed point and scientific notation while still requiring a decimal point. If you look at the output of this example you'll see that it isn't just fixed point notation:
#include <iostream>
int main() {
for (double value(1e15), divisor(1); divisor < 1e20; divisor *= 10) {
std::cout << std::noshowpoint << (value / divisor) << '\t'
<< std::showpoint << (value / divisor)
<< '\n';
}
}
This yields the output
1e+15 1.00000e+15
1e+14 1.00000e+14
1e+13 1.00000e+13
1e+12 1.00000e+12
1e+11 1.00000e+11
1e+10 1.00000e+10
1e+09 1.00000e+09
1e+08 1.00000e+08
1e+07 1.00000e+07
1e+06 1.00000e+06
100000 100000.
10000 10000.0
1000 1000.00
100 100.000
10 10.0000
1 1.00000
0.1 0.100000
0.01 0.0100000
0.001 0.00100000
0.0001 0.000100000