Decimal, exponential

Output 3.1415926、12345678.123456789 Decimals of 、 Exponential form .
Format .
Input format : nothing
Output format : Output is real , The blank space to separate
Examples
Input : nothing
Output : 3.141593 3.141593e+000
         12345678.123457   1.234568e+007

#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;
    i++;
}
printf(" %.6lfe+",a);
cout << setw(3) << setfill('0')<< i;
return ;
}
int main(){
    solve(a);
    cout << endl;
    solve(b);
    return 0;
}