Specifying the precision when printing a float/double in C using printf

Question

I wanted to create a function that would print my array of doubles using a specified floating point precision as an argument to the function. Let's say i have the following code:

void printDoubleArrayPrecision(int length, double *arr, int precision) {
    printf("[");
    if (length > 0) {
        printf("%.2lf", arr[0]);
        for (int i = 1; i < length; i++) {
            printf(",%.2lf", arr[i]);
        }
    }
    printf("]\n");
}

Is there any way of replacing the 2 in printf(",%.2lf", arr[i]); with the given argument precision?

score 2 · Accepted Answer · answered Dec 21 '18 at 18:25

2

There is actually a possibility in printf:

printf("%.*lf", precision, arr[i]);

will print arr[i] with the given precision.

answered Dec 21 '18 at 18:25

Osiris

2,783
9
17

Note: the `"l"` in `"%.*lf"` is optional here. Use it or not, whatever brings more clarity to the code. – chux - Reinstate Monica Dec 21 '18 at 23:30

score 1 · Answer 2 · answered Dec 21 '18 at 18:28

1

Apparently i should've searched for my solution by looking for printing strings with variable length instead of doubles. A solution for my question would be:

printf(",%.*lf", precision, arr[i]);

answered Dec 21 '18 at 18:28

Cornul11

191
1
12

Specifying the precision when printing a float/double in C using printf

2 Answers2