Delphi中的算术运算函数

函数名ABS简要介绍：Returns an absolute value. (取绝对值）所属单元：System定义：function Abs(X);详细解释：Abs returns the absolute value of the argument, X.
X is an integer-type or real-type expression.
(Abs函数用于返回变量X的绝对值,X可以是一个整形的变量或实数型的变量) 

返回

函数名ceil简要介绍：Rounds variables up toward positive infinity.所属单元：Math定义：function Ceil(X: Extended):Integer详细解释：Call Ceil to obtain the lowest integer greater than or equal to X. The absolute value of X must be less than MaxInt. For example:
Ceil(-2.8) = -2
Ceil(2.8) = 3
Ceil(-1.0) = -1

(调用ceil函数，返回大于或等于x的最小整数值。X的绝对值一定要小于最大整数值。例如：
Ceil(-2.8) = -2

Ceil(2.8) = 3

Ceil(-1.0) = -1)

 返回函数名Exp简要介绍：Returns the exponential of X.(Exp函数返回自然对数基底E的X次幂。)所属单元：System定义：function Exp(X: Real): Real;详细解释：

Exp returns the value of e raised to the power of X, where e is the base of the natural logarithms.
(Exp返回e的X次幂的值，其中e是一个自然对数基底。)

范例：

var   e : real;   S : string;begin   e := Exp(1.0);   Str(ln(e):3:2, S);   S := 'e = ' + FloatToStr(e) + '; ln(e) = ' + S;   Canvas.TextOut(10, 10, S);end;

 

返回

函数名Floor简要介绍：Rounds variables toward negative infinity.(取小于给定值的最大整数)所属单元：Math定义：function Floor(X: Extended): Integer;详细解释：

Call Floor to obtain the highest integer less than or equal to X. For example:

Floor(-2.8) = -3

Floor(2.8) = 2

Floor(-1.0) = -1

Note: The absolute value of X must be less than MaxInt.

(使用Floor函数以取得小于等于X的最大的整数，如：
Floor(-2.8) = -3

Floor(2.8) = 2

Floor(-1.0) = -1

注意：X的绝对值必须小于整形数的最大值)

返回

函数名Frac简要介绍：Returns the fractional part of a real number(返回一个实数的小数部分)所属单元：System定义：function Frac(X: Extended): Extended;详细解释：

The Frac function returns the fractional part of the argument X.

X is a real-type expression. The result is the fractional part of X; that is, Frac(X) = X - Int(X).

(Frac函数返回参数X的小数部分，X是一个实型数,该函数的作用等价于Frac(X)=X-Int(X)。)

范例：

vara,b:Real;begina := 1.54;b := frac(a);end;此时，a= 1.54,b=0.54

返回

函数名Frexp简要介绍：Separates the Mantissa and Exponent of X(分解开X的尾数和指数。)所属单元：Math定义：procedure Frexp(X: Extended; var Mantissa: Extended; var Exponent: Integer) register;详细解释：

Frexp returns the mantissa of X as Mantissa and the exponent as Exponent.(Frexp函数返回X的尾数用变量Mantissa和指数用变量Exponent)。

返回

函数名int简要介绍：Returns the integer part of a real number.(返回一个实数类型的整数部分)所属单元：System定义：function Int(X: Extended): Extended;详细解释：

Int returns the integer part of X; that is, X rounded toward zero. X is a real-type expression.(Int函数返回参数X的整数部分，X为实数类型，函数结果为X经过负向舍入(向0舍入)实数。) 

范例：

var   R: Real;begin  R := Int(123.456);    { 123.0 }  R := Int(-123.456);   { -123.0 }end;

返回

函数名Intpower简要介绍：Calculates the integral power of a base value.(计算基数的整数幂。)所属单元：Math定义：function IntPower(Base: Extended; Exponent: Integer): Extended register;详细解释：

IntPower raises Base to the power specified by Exponent

(计算基数的整数幂。base为基数，Exponent为指数)

范例：

返回

函数名Ldexp简要介绍：Calculates X * (2**P)所属单元：Math定义：function Ldexp(X: Extended; P: Integer): Extended register;详细解释：

Ldexp returns X times (2 to the power of P).
(Ldexp计算X*(2**P)，返回X的(2的P次幂)次幂。)

返回

函数名Max简要介绍：Returns the greater of two numeric values.(取两个数中的最大值)所属单元：Math定义：

function Max(A,B: Integer): Integer; overload;function Max(A,B: Int64): Int64; overload;function Max(A,B: Single): Single; overload;function Max(A,B: Double): Double; overload;function Max(A,B: Extended): Extended; overload;

详细解释：

Call Max to compare two numeric values. Max returns the greater value of the two.
(返回两个数值中的最大值。调用Max比较两个数值。它返回二者中较大的一个值。)

返回

函数名Min简要介绍：Returns the lesser of two numeric values.(取两个数的最小值)所属单元：Math定义：function Min(A,B: Integer): Integer; overload;
function Min(A,B: Int64): Int64; overload;
function Min(A,B: Single): Single; overload;
function Min(A,B: Double): Double; overload;
function Min(A,B: Extended): Extended; overload;详细解释：

Call Min to compare two numeric values. Min returns the smaller value of the two.
(返回两个数值中的最小值。调用Max比较两个数值，它返回二者中较小的一个值。)

返回

函数名pi简要介绍：Returns 3.1415926535897932385. (返回3.1415926535897932385.)所属单元：System定义：function Pi: Extended;详细解释：

Use Pi in mathematical calculations that require pi, the ratio of a circle's circumference to its diameter. Pi is approximated as 3.1415926535897932385.
(使用Pi函数精确计算返回圆周率Pi，圆周率是一个圆的周长除以它的直径。Pi的值近似于3.1415926535897932385.)

返回

函数名poly(本条翻译无把握)简要介绍：Evaluates a uniform polynomial of one variable at the value X.所属单元：Math定义：function Poly(X: Extended; const Coefficients: array of Double): Extended;详细解释：

Call Poly to evaluate the polynomial represented by the Coefficients parameter at the point where the variable equals the value of the X parameter. The coefficients are ordered in increasing powers of X:

Coefficients[0] + Coefficients[1]*X + ... + Coefficients[N]*(X**N)
(Poly估计一个变量在同一多项式的X值。调用Poly评估由Coefficients参数表达的多项式在一位置的值等同于X参数的值。参数是顺序的以X的幂增加：Coefficients[0]+
coefficients[1]*X+…..+Cofficients[n]*[X**N])

返回

函数名power简要介绍：Raises Base to any power.(取一个实数的幂）所属单元：Math定义：function Power(Base, Exponent: Extended): Extended;详细解释：

Power raises Base to any power. For fractional exponents or exponents greater than MaxInt, Base must be greater than 0.
（返回一个实数的幂。 当指数Exponent为小数或大于MaxInt时，底数Base必须大于0.）

返回

函数名Round简要介绍：Returns the value of X rounded to the nearest whole number.(对一个实数进行四舍五入)所属单元：System定义：function Round(X: Extended): Int64;详细解释：

The Round function rounds a real-type value to an integer-type value.

X is a real-type expression. Round returns an Int64 value that is the value of X rounded to the nearest whole number. If X is exactly halfway between two whole numbers, the result is always the even number.

If the rounded value of X is not within the Int64 range, a run-time error is generated, which can be handled using the EInvalidOp exception.

(Round返回X向最近整数值的舍入。
函数将一个实型值舍入为一个整型值。X是一个实型表达式。Round返回一个长整型值，是离X最近的整数值。如果X是两个整数值的正中间，结果是绝对值最大的一个。如果X的舍入值不是在长整型范围内，一个运行时间错误将产生，可以使用EinvalidOp异常来处理)

范例：

var   S, T: string;begin   Str(1.4:2:1, T);   S := T + ' rounds to ' + IntToStr(Round(1.4)) + #13#10;   Str(1.5:2:1, T);   S := S + T + ' rounds to ' + IntToStr(Round(1.5)) + #13#10;   Str(-1.4:2:1, T);   S := S + T + ' rounds to ' + IntToStr(Round(-1.4)) + #13#10;   Str(-1.5:2:1, T);   S := S + T + ' rounds to ' + IntToStr(Round(-1.5));   MessageDlg(S, mtInformation, [mbOk], 0);end;

返回

函数名Sqr简要介绍：Returns the square of a number.(取给定值的平方)所属单元：System定义：function Sqr(X: Extended): Extended;详细解释：

The Sqr function returns the square of the argument.

X is a floating-point expression. The result, of the same type as X, is the square of X, or X*X.
(Sqr返回X得平方值，X是一个浮点型的数,返回值的类型与X 相同,值为X*X)

范例：var
S, Temp: string;
begin
Str(Sqr(5.0):3:1, Temp);
S := '5 squared is ' + Temp + #13#10;
Str(Sqrt(2.0):5:4, Temp);
S := S + 'The square root of 2 is ' + Temp;
MessageDlg(S, mtInformation, [mbOk], 0);
end;

返回

函数名sqrt简要介绍：Returns the square root of X.所属单元：System定义：function Sqrt(X: Extended): Extended;详细解释：

X is a floating-point expression. The result is the square root of X.
(取X的平方根,X是一个浮点数，返回值也是个浮点数)

范例：var
S, Temp: string;
begin
Str(Sqr(5.0):3:1, Temp);
S := '5 squared is ' + Temp + #13#10;
Str(Sqrt(2.0):5:4, Temp);
S := S + 'The square root of 2 is ' + Temp;
MessageDlg(S, mtInformation, [mbOk], 0);
end;

返回

函数名Trunc简要介绍：Truncates a real number to an integer.(截取一个实数的整数部分)所属单元：System定义：function Trunc(X: Extended): Int64;详细解释：

The Trunc function truncates a real-type value to an integer-type value. X is a real-type expression. Trunc returns an Int64 value that is the value of X rounded toward zero.

If the truncated value of X is not within the Int64 range, an EInvalidOp exception is raised.

范例：var
S, T: string;
begin
Str(1.4:2:1, T);
S := T + ' Truncs to ' + IntToStr(Trunc(1.4)) + #13#10;
Str(1.5:2:1, T);
S := S + T + ' Truncs to ' + IntToStr(Trunc(1.5)) + #13#10;
Str(-1.4:2:1, T);
S := S + T + ' Truncs to ' + IntToStr(Trunc(-1.4)) + #13#10;
Str(-1.5:2:1, T);
S := S + T + ' Truncs to ' + IntToStr(Trunc(-1.5));
MessageDlg(S, mtInformation, [mbOk], 0);
end;