Any help with bool and float

Hi.I'm trying to "make" triangle validation with bool and float.And that is OK.My problem is how to "mutate" bool return into string so I can printf it.Yes,I'm total beginner,but I try. Thank's in advance.
TF.txt open in Sublime or ...

Code:

---

#include <stdio.h>
#include <cs50.h>

bool val_tri(float x, float y, float z);

int main(void)
{
    float x = get_float("first side: ");
    float y = get_float("second side: ");
    float z = get_float("third side: ");


    printf("triangl is %s.\n", tf);
}

bool val_tri(float x, float y, float z)
{
    if (x < 0 || y < 0 || z < 0)
    {
        return false;
    }
    if ((x + y <=z) || (x + z <= y) || (y + z <= x))
    {
        return false;
    }

    return true;
}

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If you want to print the value of a bool you can either print it as an int where it will print as 0 for false and 1 for true, or you can print it as a string.

Code:

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// as int
printf("bool: %d\n", (int)bool_value);
 
// as string
printf("bool: %s\n", bool_value ? "true" : "false");

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As a string...Thank you.