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The expression means a structure composed of constants, variables, operator symbols, functions, brackets. The expression defines the procedure for calculation of the certain value. Operation applied to one operand is called unary and operation with two operands  binary.
Arithmetic operations
Binary arithmetic operations include:
+ addition
 subtraction
* multiplication
/ division
% division modulo; (this operation is similar to operation mod in Pascal  the remainder of the division). Operation % applies only to integer numbers
Unary operations include:
++ increase by one (increment);
  decrease by one (decrement);
For example: x=x+1, x++, ++x the result of the two operations is the same.
Both operation signs can be recorded mark both before operand (prefix form) and after operand (postfix form), for example ++хorх++,––хorх––. When using postfix form, the operations ++ and   are performed after the value of the variable was used in the expression and the prefix operation  until use.
For example: 1) x=5; y=x++; firstly, value х is assigned to variable у, after value хis increased by 1. Initial value х=5, after performance of operations y=5, x=6.
2) x=5; y=++x; result of operation x=6, y=6.
3) a=3; c=2; x=a++ * c++; result of operation a=4, c=3, x=6.
4) a=3; c=2; x=++a * ++c; result of operation a=4, c=3, x=12.
Relational operations
C uses the same set of relational operations, as in other programming languages:
< less
<= less or equal
> greater
>= greateror equal
== equal
!= not equal
The difference is in the recording of operations “equal” and “not equal”.
Therefore, the result of the relational operation is the integer number: if the relation is true –then 1, if false  then 0.
For example: the result of the relational operation in case 5>1, ‘x’==’x’ will equal 1, and in case 5!=5, ‘x’==’X’ result=0.
Logical operations
Basic logical operations in С++ language will be recorded as follows:
&&  conjunction (logic “AND”)
  disjunction (logic“OR”)
!  inversion (logic“NOT”)
Table 2 below shows examples of recording expressions in C ++ language using logical operations and relational operations.
Table 2. Recording of expressions
mathematical expression 
recording inС++ 
0<x<10 
x>0 && x<10 
y≤1 или y≥1 
y<=1  y>=1 
x≠y 
!(x= =y) 
a=b 
a= =b 
‘a’≠’A’ 
‘a’!=’A’ 
Priority to perform logical operations and relational operations as follows:
Assignment operation
General view of the assignment operation as follows:
Name of variable = expression;
For example: x=5; D=b*b4*a*c; a=b=0;
Assignment operation in C language is not operand, i.e. assignment as any other sign of operation can several times enter the expression.
For example: а=b=c=x+y;
Also in С++ language, assignment operation can be combined with other operations: +=, =, /=, *=, %=
For example: The following expressions are considered as equivalent.
i+=2 and i=i+2
p/=5 and p=p/5
a*=b+c and a=a*(b+c)
x=y andx=xy
n%2 andn=n%2
Instead of expression х=х+2 it is preferable to use recordх+=2, since the second expression will be calculated faster.
Operation“condition”
This is the only operation that has three operands. The format of the operation:
logical operation ? expression 1: expression 2;
or
variable = logical operation? expression 1: expression 2;
This operation implements the algorithmic branch structure. The algorithm of its performance is as follows: the value of the logical expression shall be calculated the first, if it is true, then the expression is calculated  1 and the obtained result becomes as the result of the operation. Otherwise, the value of the expression2 is taken as the result.
For example:
x<0 ? –x: x;
max=(a<=b) ? b : a;
a>b ? 2*a: 2*b;
Functions that are calculated automatically by special modules are called standard functions. They are stored in the header file math.h
Standard functions ofС++ language are shown in Table 3.
Table 3. Standard functions ofС++ language
Mathematical function 
Record onС++ 
Argument type 
Result type 
Note 
 x  
abs (x) 
int 
int 
absolute value of integer number 
 x  
fabs (x) 
double 
double 
absolute value of real number 
sinx 
sin(x) 
double 
double 
х radian 
cosx 
cos(x) 
double 
double 
х radian 
tgx 
tan(x) 
double 
double 
х radian 
e ^{x} 
exp(x) 
double 
double 
e = 2,718 … 
lnx 
log(x) 
double 
double 
natural logarithm, x>0 
lg(x) 
log10(x) 
double 
double 
decimal logarithm 
sqrt(x) 
double 
double 
square root, x>=0 

x^{y} 
pow(x,y) 
double, double 
double 
x in power of y 
10^{p} 
pow10(p) 
int 
double 
10in power of p 
arcsinx 
asin(x) 
double 
double 
х radian 
arccosx 
acos(x) 
double 
double 
х radian 
arctgx 
atan(x) 
double 
double 
х radian 
sinhx 
sinh(x) 
double 
double 
hyperbolic sine,х radian 
coshx 
cosh(x) 
double 
double 
hyperbolic cosine,х radian 
tanhx 
tanh(x) 
double 
double 
hyperbolic tangent, х radian 
nearest integer, not less х 
ceil(x) 
double 
double 
the result will be displayed in format double 
greatest integer, not exceeding х 
floor(x) 
double 
double 
the result will be displayed in format double 
remainder of the division of integer хonу 
fmod(x,y) 
double, double 
double 
the result will be displayed in format double 
z^{2}=x^{2}+y^{2} 
hypot(x,y) 
double, double 
double 
calculates hypotenuse of the rectangular triangle according tolegs value z2=x2+y2 
All other functions are expressed through the standard. Examples of recording of mathematical expressions in C ++ language:
9. e ^{sinx}® exp (sin(x))
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