Find Employee Gross salary

#include<stdio.h>
double salary(float basic);
void main()
{
    float basic,gross;
    printf("What is your basic pay?");
    scanf("%f",&basic);
    gross=salary(basic);
    printf("\n your Gross Salary is %f",gross);
    printf("\nThank you!!");
}
double salary(float basic)
{
    float ta,da;
    ta=(12*basic)/100;
    da=(10*basic)/100;
    return(basic+ta+da);
}