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Mathematical operators
The basic mathematical operators are the
same as the ones available in most programming languages: addition
(+),
subtraction (-),
division (/),
multiplication (*), and
modulus (%; this produces
the remainder from integer division). Integer division truncates the result (it
doesn’t round). The modulus operator cannot be used with floating-point
numbers.
C and C++ also use a shorthand notation
to perform an operation and an assignment at the same time. This is denoted by
an operator followed by an equal sign, and is consistent with all the operators
in the language (whenever it makes sense). For example, to add 4 to the variable
x and assign x to the result, you say: x += 4;.
This example shows the use of the
mathematical operators:
//: C03:Mathops.cpp
// Mathematical operators
#include <iostream>
using namespace std;
// A macro to display a string and a value.
#define PRINT(STR, VAR) \
cout << STR " = " << VAR << endl
int main() {
int i, j, k;
float u, v, w; // Applies to doubles, too
cout << "enter an integer: ";
cin >> j;
cout << "enter another integer: ";
cin >> k;
PRINT("j",j); PRINT("k",k);
i = j + k; PRINT("j + k",i);
i = j - k; PRINT("j - k",i);
i = k / j; PRINT("k / j",i);
i = k * j; PRINT("k * j",i);
i = k % j; PRINT("k % j",i);
// The following only works with integers:
j %= k; PRINT("j %= k", j);
cout << "Enter a floating-point number: ";
cin >> v;
cout << "Enter another floating-point number:";
cin >> w;
PRINT("v",v); PRINT("w",w);
u = v + w; PRINT("v + w", u);
u = v - w; PRINT("v - w", u);
u = v * w; PRINT("v * w", u);
u = v / w; PRINT("v / w", u);
// The following works for ints, chars,
// and doubles too:
PRINT("u", u); PRINT("v", v);
u += v; PRINT("u += v", u);
u -= v; PRINT("u -= v", u);
u *= v; PRINT("u *= v", u);
u /= v; PRINT("u /= v", u);
} ///:~
The rvalues of all the assignments can,
of course, be much more complex.
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