Using a variable as format specifier in C

It is known that, printf() function is an inbuilt library function in C programming language in the header file stdio.h. It is used to print a character, string, float, integer etc. onto the output screen. However, while printing the float values, the number of digits following the decimal point can be controlled by the user. One of the ways to do that is by using formats like %.2f etc. But variables can also be used for formatting format specifiers.

Below example shows how this can be done.

// C program to demonstrate use of variable 
// in format specifier. 
#include <stdio.h> 
  
int main() 
{ 
    float b = 6.412355; 
  
    // using the format specifier %.*f 
    // a = 3 will print value of b upto 
    // 3 decimal places 
    int a = 3; 
    printf("%.*f\n", a, b); 
  
    // a = 5 will print value of b upto 
    // 3 decimal places 
    a = 5; 
    printf("%.*f\n", a, b); 
    return 0; 
} 

Output:

6.412
6.41235

This article is contributed by MAZHAR IMAM KHAN. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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