# Arithmetic and logical binary operators in matlab

It is considered poor style to write code that relies upon this behavior and different programming languages may use different rules. This allows statements like if s! Precedence order gone awry. Sometimes the precedence order defined in a language do not conform with mathematical norms. This rule agrees with mathematical conventions for all C operators, but fails with the addition of the exponentiation operator.

Once the order was established in Microsoft Excel 2. What is the result of the following code fragment? String concatenation and addition have the same precedence. Since they are left-associative, the operators are evaluated left-to-right. Add parentheses to the following expression to make the order of evaluation more clear. Last modified on July 27, Writing Clear Code C. Matlab Programming Assignments Appendix A: Level Operator Description Associativity For example, consider the following code fragment:.

You might think that this sets negative entries in x to and positive entries to But in fact, all it does is set the array x to the scalar value The first statement x will only be true if all entries of x are negative.

Since we probably have a mix of both positive and negative entries, the code will set x to the scalar value Sometimes, you may want to know the indices of the entries in an array that meet some criteria.

For example, suppose we wanted to know where the first non-zero number in an array occurs. The Matlab find function will return for us an array of indices at which some logically array is set to true.

The array idx contains the indices of the positive entries. If no entries are found meeting the criteria, then find returns an empty array. In this lab, you will practice using conditional statements. Use a mask to find all the entries in the vector x that are between Plot the following discontinuous function over the interval [-5,5]. Be sure to include any end point conditions.

Use only an array 'mask' to select points to include in each piece. Do you want to try the above code fragments on your own? Download the Matlab script that produces this page here. Back to tutorial index Using logical operators and conditional statements Topics in this lab Logical operators Using logical operators with arrays Conditional statements Using arrays in conditional statements Using the Matlab 'find' function Lab exercises.

Logical operators Another key concept in programming is the ability to test a conditional statement and make decisions about the flow of the program based on the truth value of the statement.

A Here are some simple examples illlustrating the use of relational or "logical" operators. Back to the top Using logical operators with arrays These relational tests, when used with Matlab arrays, produce another array whose entries are '0' where the relational test is false, and '1' where the relational statement is true. For example, we can pull out only the positive entries of x: Or, we can pull out only the negative entries of x: Back to the top Conditional statements Where these logical statements become useful is when they can be used to control the flow of a program.

The real roots are: Back to the top Using arrays in conditional statements We can also use conditional statements in arrays.