EE208 C Programming

It happens when type of the expression on RHS and variable on LHS of the assignment operator (=) are not of the same type.

Rule - value of the expression is promoted or demoted depending upon the type of the variable on LHS of the = (assignment). 

e.g. 

int a ; 
flaot b;
a = 3.5 ;  
b = 30 ; 

In instruction third  a=3.5 value on RHS (3.5) is float. It can't be stored in varible a as it is int. Therefore in this case value of float 3.5 is demoted to int and then it is stored in the variable.

Hence value 3 is stored in the variable a. 

b = 30 ;  

As b is float therefore value on RHS is promoted to float type (30.000000) and then it is stored in the varibale b.