Explain this floating point behavior

Question

Please explain why the following pieces of code behave differently.

#include
int main(){
 float a=0.1;
 if(a<0.1)
  printf(\"less\");
 else         


        

Answer 1

#include

int main() {
    float a = 0.7;
    if (a < 0.7)
        printf("less");
    else 
        printf("greater than equal");
    getchar();
}

Unsuffixed floating constants are of type double not float. For example, 0.7 is a floating constant of type double.

if (a < 0.7)

As the right operand in the comparison expression is of type double, the usual arithmetic conversion apply and the a value is promoted to double. double and float don't have the same precision. In your case to get the correct result you should have used a floating constant of type float.

if (a < 0.7f)

0.7f is a floating constant of type float.