C Tutorial/printf scanf/printf Precision

For floating arguments, precision indicates how many digits are printed after decimal points.

<source lang="cpp">#include <stdio.h> main() {

   printf("%10.4e\n", 35.99999);

}</source>

3.6000e+01

Precision

Precision indicates the minimum number of digits printed for type integers d, i, o, u, x, and X.

<source lang="cpp">#include <stdio.h> main() {

   printf("%10.4d\n", 35);

}</source>

0035

1. 10 is the field-width.
2. 4 is the precision.

Using precision while printing integers, floating-point numbers, and strings

<source lang="cpp">#include <stdio.h> int main() {

  int i = 873;
  double f = 123.94536;        
  char s[] = "Happy Birthday"; 
  printf( "Using precision for integers\n" );
  printf( "\t%.4d\n\t%.9d\n\n", i, i );
  printf( "Using precision for floating-point numbers\n" );
  printf( "\t%.3f\n\t%.3e\n\t%.3g\n\n", f, f, f );  
  
  printf( "Using precision for strings\n" );
  printf( "\t%.11s\n", s );
  return 0;

}</source>

Using precision for integers
        0873
        000000873
Using precision for floating-point numbers
        123.945
        1.239e+02
        124
Using precision for strings
        Happy Birth