Ok - First, make sure your main() function returns a value.
Secondly you did not prototype the function count(), which was causing your error I think. If you are going to define a function after you call it in your source code you have to prototype the function to ensure the compiler knows what to expect.
You also didn't declare the int total before you used it.
// Prototype of function count
float count(float , float );
// Didn't declare this
printf("Enter Your Salary : ");
printf("Enter Your Sale : ");
printf("Total Salary : %f",count(sale,salary) );
float count(float sale, float salary)
bonus = sale * 0.5;
else if ( sale >=500000)
bonus = sale * 0.3;
bonus = sale * 0.1;
total = salary + bonus;