Setting decimal precision in C

How to print floating point numbers with a specified precision? Rounding is not required. For example, 5.48958123 should be printed as 5.4895 if given precision is 4.

For example, below program sets the precision for 4 digits after the decimal point:

// C program to set precision in floating point numbers
#include<stdio.h>
#include<math.h>
int main()
{
   float num = 5.48958123;

   // 4 digits after the decimal point
   num = floor(10000*num)/10000;

   printf("%f", num);
   return 0;
}

Output:

5.489500

We can generalize above method using pow()

float newPrecision(float n, float i)
{
    return floor(pow(10,i)*n)/pow(10,i);
}

In C, there is a format specifier in C. To print 4 digits after dot, we can use 0.4f in printf(). Below is program to demonstrate the same.

// C program to set precision in floating point numbers
// using format specifier
#include<stdio.h>

int main()
{
    float num = 5.48958123;

    // 4 digits after the decimal point
    printf("%0.4f", num);
    return 0;
}

Output:

5.4896

If you like GeeksforGeeks and would like to contribute, you can also write an article and mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above