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Why should we use 'f' with float literal in C?

By: IncludeHelp, on 23 JAN 2017

Consider the following statement

float x=10.23;

Here, 10.23 is not a float value it's double type, which is converting into float type implicitly while assigning in x.

Let's prove it, consider the following statement


This statement will return 8, while float takes 4 bytes in the memory. So, it's double because double takes 8 bytes in the memory.

Correct form of float literal

Consider the following statement

float x=10.23f;

Here, 10.23f is a correct float literal representation and if we print its size it will be 4.

Consider the following program; here we are printing size of 10.23 and 10.23f.

#include <stdio.h>
int main()
	printf("size of double literal: %d\n",sizeof(10.23));
	printf("size of float literal: %d\n",sizeof(10.23f));
	return 0;


    size of double literal: 8 
    size of float literal: 4