Question

how to evaluate logical expression in programming in c

Answer 1

Answer:

Logical Operators:

They are used to combine two or more conditions/constraints or to complement the evaluation of the original condition under consideration. They are described below:

Logical AND operator: The ‘&&’ operator returns true when both the conditions under consideration are satisfied. Otherwise it returns false. For example, a && b returns true when both a and b are true (i.e. non-zero).

Logical OR operator: The ‘||’ operator returns true even if one (or both) of the conditions under consideration is satisfied. Otherwise it returns false. For example, a || b returns true if one of a or b or both are true (i.e. non-zero). Of course, it returns true when both a and b are true.

Logical NOT operator: The ‘!’ operator returns true the condition in consideration is not satisfied. Otherwise it returns false. For example, !a returns true if a is false, i.e. when a=0.

Explanation:

#include <stdio.h>  

 

int main()  

{  

   int a = 10, b = 4, c = 10, d = 20;  

 

   // logical operators  

 

   // logical AND example  

   if (a > b && c == d)  

       printf("a is greater than b AND c is equal to d\n");  

   else

       printf("AND condition not satisfied\n");  

 

   // logical AND example  

   if (a > b || c == d)  

       printf("a is greater than b OR c is equal to d\n");  

   else

       printf("Neither a is greater than b nor c is equal "

              " to d\n");  

 

   // logical NOT example  

   if (!a)  

       printf("a is zero\n");  

   else

       printf("a is not zero");  

 

   return 0;  

}

Answer 2

$\large{\bullet{\underline{\texttt{Evaluating logical expressions:-}}}}$

• The precedence of logical operator is lower than the arithmetic operators so constituent arithmetic sub- expression ( if any ) is evaluated first and then logical operator are applied.
• The precedence of logical operator among themselves is not and or So, the expression a or b and c will be evaluated.
• Important while Evaluating python minimise internal work by following three rules :

1. In or evaluation, python only evaluates the second argument if the second argument if the first one is true evaluated.