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

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

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