CalculatorOfBonus.c

#include<stdio.h>
int main(void){
	int current_year = 0; 
	int year_of_joining = 0;
	float year_of_services = 0.0f;
	float bonus = 0.0f;
	printf("please enter current year:");
	scanf("%d", &current_year);
	printf("please enter year of joining:");
	scanf("%d", &year_of_joining);
	year_of_services = current_year = year_of_joining;
	if(year_of_services > 3)
	{
		  bonus = 2500.0f;
		  printf("Calculated Bonus Rs: %.2f\n", bonus);
	}
return 0;	
}

1. Every variable should not be float, think what should type of value you want to store.
2. current_year and year_of_joining variables can be int simply.
3. Line 11 should be year_of_services = current_year - year_of_joining;