Why the loop doesn't stop ?

Question

#include <stdio.h>
int main(void){
double a = 3.0, b = 3.4;
while(a != b){
puts("Not Equal.");
a = a + 0.1;
}
puts("Now Equal");
getchar();
return 0;
}

// If b = 3.1 or 3.2 it works perfectly.

Answer 1

garbage digits are causing a round-off error which prevents them from becoming equal.

 

Try this:

 

   while (a <= b)

  {

       puts(" Not equal ");

        a += 0.1;

  }

 puts(" value exceeded ");