Skip to main content

Parentheses and Priority


Parentheses are classed as operators by the compiler, although their position
is a bit unclear. They have a value in the sense that they assume the value
of whatever expression is inside them. Parentheses are used for forcing a
priority over operators. If an expression is written out in an ambiguous way,

such as:

 a + b / 4 * 2

it is not clear what is meant by this. It could be interpreted in several ways:

((a + b) / 4) * 2
or
(a + b)/ (4 * 2)
or
a + (b/4) * 2



and so on. By using parentheses, any doubt about what the expression
means is removed. Parentheses are said to have a higher priority than + *
or / because they are evaluated as "sealed capsules" before other operators
can act on them. Putting parentheses in may remove the ambiguity of
expressions, but it does not alter than fact that

a + b / 4 * 2

is ambiguous. What will happen in this case? The answer is that the C
compiler has a convention about the way in which expressions are evaluated:
it is called operator precedence. The convention is that some operators are
stronger than others and that the stronger ones will always be evaluated first.
Otherwise, expressions like the one above are evaluated from left to right: so
an expression will be dealt with from left to right unless a strong operator
overrides this rule. Use parentheses to be sure. A table of all operators and
their priorities is given in the reference section.
Labels:

Popular posts from this blog

Putimage function in c

putimage function outputs a bit image onto the screen. Declaration:- void putimage(int left, int top, void *ptr, int op); putimage puts the bit image previously saved with getimage back onto the screen, with the upper left corner of the image placed at (left, top). ptr points to the area in memory where the source image is stored. The op argument specifies a operator that controls how the color for each destination pixel on screen is computed, based on pixel already on screen and the corresponding source pixel in memory. c smiling face animation This animation using c draws a smiling face which appears at random position on screen. See output below the code, it will help you in understanding the code easily. C programming code #include<graphics.h> #include<conio.h> #include<stdlib.h>   main() { int gd = DETECT, gm, area, temp1, temp2, left = 25, top = 75; void *p;   initgraph(&gd,&gm,"C:\\TC\\BGI");   setcolor(YELLOW)...
Read more

C++ Program to find the sum, difference, product and quotient of two integers

#include <iostream.h> #include <conio.h> void main() {   clrscr();   int x = 10;   int y = 2;   int sum, difference, product, quotient;   sum = x + y;   difference = x - y;   product = x * y;   quotient = x / y;   cout << "The sum of " << x << " & " << y << " is " << sum << "." << endl;   cout << "The difference of " << x << " & " << "y <<  is " << difference << "." << endl;   cout << "The product of " << x << " & " << y << " is " << product << "." << endl;   cout << "The quotient of " << x << " & " << y << " is " << quotient << "." << endl;   getch(); }
Read more

What are selection statements in C++ ? If and Switch

There are several statements that we can use in C++ programming that help in choosing a set of instructions for using the code depending upon an expression truth value.  What are Selection Statements in C++? As mentioned above there are several statements that we can use to choose a set of pre-defined instructions within a program in any section of the program as per the need. These are called selection statements in C++  In C++ Program there are two types of Selection statements  1. If  2. Switch  The If Statement of C++ To understand "if statement" let's look at an example.  Example - If you have 10 rupees then you can buy the chocolate.  Here, there is a condition in buying chocolate, if you have 10 rupees then only you can buy it.  This shows that the If is a condition which can be true or false, If it is false it won't be executed, in this example, if you don't have 10 rupees i.e. the condition is false you cant buy the chocolate.  So, I...
Read more