I have started to learn C and I tried my hand at temperature conversion. The idea is to convert a temperature from Fahrenheit to Celsius and vice/versa. Can somebody review my code and let me know how I might be able to improve it. My program is as follows:

#include <stdio.h>


void fahconv()
{
    double fah;
    puts("Enter value to convert from Fahrenheit to Celsius");
    scanf("%lf",&fah);
    printf("Converted temperature from F to C: %lf",((fah - 32.0)*5.0)/9.0);
}

void celsconv()
{
    double cels;
    puts("Enter value to convert from Celsius to Fahrenheit");
    scanf("%lf",&cels);
    printf("Converted temperature from C to F: %lf",(cels*9/5)+32);
}

void invalidchoice()
{
    printf("Invalid choice..exiting");
}

int main()
{
    char choice;
    puts("Enter (F or f) to convert from Fahrenheit to Celsius");
    puts("Enter (C or c) to convert from Celsius to Fahrenheit \n");
    scanf("%c",&choice);
    switch(choice)
    {
        case 'c': 
        case 'C': celsconv();
              break;
        case 'f': 
        case 'F': fahconv();
              break;
        default: invalidchoice();
    }
    return 0;
}

I have started to learn C and I have tried my hand at temperature conversion. The idea is to convert a temperature from Fahrenheit to Celsius and vice/versa. Can somebody review my code and let me know how I might be able to improve it? My program is as follows:

#include <stdio.h>


void fahconv()
{
    double fah;
    puts("Enter value to convert from Fahrenheit to Celsius");
    scanf("%lf",&fah);
    printf("Converted temperature from F to C: %lf",((fah - 32.0)*5.0)/9.0);
}

void celsconv()
{
    double cels;
    puts("Enter value to convert from Celsius to Fahrenheit");
    scanf("%lf",&cels);
    printf("Converted temperature from C to F: %lf",(cels*9/5)+32);
}

void invalidchoice()
{
    printf("Invalid choice..exiting");
}

int main()
{
    char choice;
    puts("Enter (F or f) to convert from Fahrenheit to Celsius");
    puts("Enter (C or c) to convert from Celsius to Fahrenheit \n");
    scanf("%c",&choice);
    switch(choice)
    {
        case 'c': 
        case 'C': celsconv();
              break;
        case 'f': 
        case 'F': fahconv();
              break;
        default: invalidchoice();
    }
    return 0;
}