Constants are simply variables that do not change value. This is particularly useful when we need to continually refer to the same value, such as the length of a fixed-length array:
const int array_max = 100;
int array[array_max];
for (int i=0; i<array_max; ++i) {
array[i] = i * i;
}
// ...
Using a constant in this way reduces the maintenance burden considerably. For example, suppose we later decide that we really needed 200 integers in our array instead of just 100. So long as our code uses the constant, array_max, we need only change the constant's value and that change will be reflected wherever the constant is used. If we has used the literal constant, 100, instead, we'd need to search through our code and update each usage of that literal. That can lead to human errors and inconsistency in our code.
All constants are allocated in the static segment (where all static variables are allocated) even when they are declare locally. The one exception is a constant formal argument:
void f (const int i) {
// ...
}
Arguments are always passed by value, so i will hold a copy of whichever value was passed to it. Being a copy, any changes made to i will not be reflected in the calling code, however if the function must not modify the value, declaring the formal argument constant ensures we don't inadvertently change the value.
Typically we use constant formal arguments when those arguments are pointers or references rather than values. When we pass an object by reference or by pointer, we are passing a copy of the object's address and this would allow the function to indirectly modify the object. This is known as a side-effect and is undesirable. To give assurance to the caller that the object will not be changed, we use a constant reference or pointer:
void f (const obj& x) {
// ...
}
If we actually want the function to modify the object, the best method of doing so is to return a new object by value and leave the argument constant:
obj f (const obj& x) {
// ...
}
In this way the caller can decide what to do with the returned object:
obj y;
obj z = f (y); // create a new object from y without changing y
y = f (y); // modify y
f (z); // ignore the modification completely
Note that returning objects by value is normally expensive as the object must be copied. However, objects that implement the move semantic can be returned extremely efficiently, particularly those objects that are really just resource handles. This includes all the standard library containers such as std::vector and std::list. Moving a vector is many times quicker than copying one because all we're really doing is changing ownership of the resource; and that's (almost) as efficient as copying a pointer and assigning NULL to the original.
...a function call.
Every C plus plus program that is a main program must have the function 'main'.
to locate coordinates ..
Because solutions of quadratic equation depend solely on these three constants.
Use the C++ getline() function from the standard library.
A function of the form f(x) = mx + c where m and c are constants is linear.
constants, MAX_(function), etc.
If it can be written in the form y = mx + c where m and c are constants [or, equivalently, ax + by = k where a, b and k are constants] then y is a linear function of x.
It can be written in the form y = ax2 + bx + c where a, b and c are constants and a ≠0
ax2 + bx + c = 0 where a, b and c are constants and a is not 0.
There is no such term as "building function" in C++.
Coding constants in c means writing the constants in a certain way that the c language understands.
"The" exponential function is ex. A more general exponential function is any function of the form AeBx, for any non-xero constants "A" and "B". Alternately, Any function of the form CDx (for constants "C" and "D") would also be considered an exponential function. You can change from one form to the other.
It is the equation of a straight line
...a function call.
The quadratic equation, in its standard form is: ax2 + bx + c = 0 where a, b and c are constants and a is not zero.
A quadratic function is a function that can be expressed in the form f(x) = ax^2 + bx + c, where a, b, and c are constants and a is not equal to 0. This function represents a parabolic shape when graphed.