Topic link ：

Code shoe set (matiji.net)

Their thinking ：

Scientific enumeration ：

• Integer counting method ：

（1）7.823E5=782300, This expression is ：E representative 10,E The following numbers represent digits , Like here 5 The representative index is 10 Of 5 Power

（2）1234567 = 1.234567E+6, This expression is ：1. It means 1.234567 Multiply by the following number , That's what's behind it E+6 It means 10 Of 6 Power

• Decimal counting

（1）1.23456e+002 , The representation of this number is ,e+002 Express 10 Of 2 Power , The number here is 123.456.

（2）202 +0.00000E+00, Such a number is expressed as 202 Add a number that is accurate to five decimal places
 

stay printf The format controller is used in the function to output decimals in exponential form

stay C++  We can use keywords scientific To achieve exponential printing

But these two methods can only output the last two digits

This topic requires the output of the last three digits

So we can write a function to find scientific counting method by ourselves

Reference code ：

#include<bits/stdc++.h> 

using namespace std;

double a = 3.1415926,b = 12345678.123456789;
void solve (double a)
{
    printf("%.6lf",a);

    int i = 0;
    while(a > 10)
    {
        a = a/10.0;// Don't forget the decimal point 
        i++;
    }

    printf(" %.6lfe+",a);

    cout << setw(3) << setfill('0') << i ;
    
    return;
}
int main( )
{
    solve(a);
    cout << endl;
    solve(b);
    return 0;
}