scientific notation

C++ How to make cout not use scientific notation

 in C++  tagged C++ / cout / fixed / I/O manipulator / scientific notation / std::fixed by

To force cout to print numbers exactly as they are and prevent it from using the scientific notation, we can use the std::fixed I/O manipulator as follows

#include <iostream>

using namespace std;

int main()
{
    std::cout << "The number 0.0001 in fixed:      " << std::fixed << 0.0001 << endl
              << "The number 0.0001 in default:    " << std::defaultfloat << 0.0001 << endl;

    std::cout << "The number 1000000000.0 in fixed:      " << std::fixed << 1000000000.0 << endl
              << "The number 1000000000.0 in default:    " << std::defaultfloat << 1000000000.0 << endl;
return 0;
}

Output

The number 0.0001 in fixed:      0.000100
The number 0.0001 in default:    0.0001
The number 1000000000.0 in fixed:      1000000000.000000
The number 1000000000.0 in default:    1e+09

C: Read a floating number that might be in the format of scientific notation

 in C  tagged C++ / scientific notation by

This code will read a floating number that might be in the format of scientific notation from the keyboard.
Then it will print out the number with the scientific notation and without it.


#include <stdio.h>
#include <stdlib.h>

int main() {
  printf("This code will read a floating number that might be in the format of scientific notation from the keyboard.\nThen it will print it out with the scientific notation and without\n");
  double input;
  printf("Enter a number in scientific notation. (e.g. -4e-5 or -4.00e-5 or -4.00e-05 etc.)\n");
  scanf("%lf", &input);
  printf("With scientific notation '%e'\n", input);
  printf("Without scientific notation '%lf'\n", input);
  return 0;
}

Examples

This code will read a floating number that might be in the format of scientific notation from the keyboard.
Then it will print it out with the scientific notation and without
Enter a number in scientific notation. (e.g. -4e-5 or -4.00e-5 or -4.00e-05 etc.)
4.5e-10
With scientific notation '4.500000e-10'
Without scientific notation '0.000000'
This code will read a floating number that might be in the format of scientific notation from the keyboard.
Then it will print it out with the scientific notation and without
Enter a number in scientific notation. (e.g. -4e-5 or -4.00e-5 or -4.00e-05 etc.)
4.5e-3
With scientific notation '4.500000e-03'
Without scientific notation '0.004500'