C++关系运算符

#include <iostream>

using namespace std;

main() {
   int a = 21;
   int b = 10;
   int c ;

   if( a == b ) {
      cout << "Line 1 - a is equal to b" << endl ;
   } else {
      cout << "Line 1 - a is not equal to b" << endl ;
   }

   if( a < b ) {
      cout << "Line 2 - a is less than b" << endl ;
   } else {
      cout << "Line 2 - a is not less than b" << endl ;
   }

   if( a > b ) {
      cout << "Line 3 - a is greater than b" << endl ;
   } else {
      cout << "Line 3 - a is not greater than b" << endl ;
   }

   /* Let's change the values of a and b */
   a = 5;
   b = 20;
   if( a <= b ) {
      cout << "Line 4 - a is either less than or equal to  b" << endl ;
   }

   if( b >= a ) {
      cout << "Line 5 - b is either greater than or equal to b" << endl ;
   }

   return 0;
}