Relational operators are good at comparing two quantities. However, relational operators does not support comparison of three or more quantities.
For example, suppose you need to check range of a number. You need to check whether a number n is in between 1-100 or not. For that you must check two conditions, first check if n > 1 finally check if n < 100.
We use logical operators to combine two or more relational expressions as a single relational expression. Logical operators evaluates a Boolean value (integer in case of C) depending upon the operator used.