Test float and double

[nagarajan1960]

Hi !
will you please explain the reasons
main()
{
float a=1.1;
double b=1.1;
if(a==b)
printf("I like you/n ");
else
printf("I hate you /n");
}

OUTPUT :
I hate you
main()
{
int a=1;
float b=1.0;
if(a==b)
printf("I like you/n ");
else
printf("I hate you /n");
}
OUTPUT :
I like you
main()
{
long double a=1.1;
double b=1.1;
if(a==b)
printf("I like you/n ");
else
printf("I hate you /n");
}
OUTPUT :
I like you

[weaknessforcats]

Read this and post again of you still have questions:

Generally, you cannot use operators like ==, !=, >, <, <=, >=, etc wth floating point numbers.
Due to the automatic rounding, these operators may report a condition as true when the numbers
are only close in value.

Google for Floating Point Arithmetic or read IEEE 754 standard specification for details.

To compare two floating point numbers, you have to establish a sigma error tolerance.

if (fabs(i - j) < 0.000001) { ... // almost equal }
 

----------------------------------------------------------------------

Also, be aware of this:

float var = 1.1;
 

Symbolic constants like 1.1 are double. A double is larger than a float so your compiler is giving
you a warning about truncation and possible loss of data as the double is converted to a float.

You should create the constant as a float by coding:

float j = 1.1f;    /* or 1.1F */
 

Further, float is a type developed in the years of computers with small memories.
Unless you can write a specific reason on paper as to why you need a float,
I recommend you use double throughout.