c++ - The #if elif directives not working as desired -

i trying test condition using if elif not getting desired results. please me in identifying doing wrong?

#include <iostream> using namespace std; #define a(t1)(t1+50) #define b(t2)(t2+100) int main() {     union gm     {         int t1;         int t2;     };     gm c;      cout <<"enter tokens earned in game 1: "<<endl;     cin>>c.t1;     int x=c.t1;     cout <<"enter tokens earned in game 2: "<<endl;     cin>>c.t2;     int y=c.t2;     int m= a(x)+100;     int n= b(y)+50;     int p;     p=m+n;     cout <<p<<endl;  #if(p<500)     cout <<"points earned less"<<endl; #elif (p>500 && p<1500)     cout<<"you can play game 1 free"<<endl; #elif (p>1500 && p<2500)     cout<<"you can play game 1 free"<<endl; #elif p>3000     cout<<"you can play game 1 , game free"<<endl; #endif     return 0; } 

when value of p exceeding 500, still showing message "points earned less".

please help.

you cannot use preprocessor macros depend on value of variable @ run time.

unless p defined preprocessor macro,

#if(p<500) 

is translated as:

#if(0<500) 

since true, block of code compiled object code. explains behavior seeing.

you need use if-else statements of c++, not preprocessor.

if (p<500) {    cout <<"points earned less"<<endl; } else if (p>500 && p<1500) {    cout<<"you can play game 1 free"<<endl; } else if (p>1500 && p<2500) {    cout<<"you can play game 1 free"<<endl; } else if ( p>3000 ) {    cout<<"you can play game 1 , game free"<<endl; } else {    // else. }