Datatype
It is the type of data, that is going to be processed within the program. A variable can be declared anywhere in the program before its first use.
Type Conversion:
(i) Implicit type conversion
(ii) Explicit type conversion
Implicit type conversion
It will be done by the compiler, by following the rule of lower type converted to higher type.
Eg: int y = 10;
float z = 10.5,x;
x = y+z; (y is converted to float type by compiler)
x = 10.0 + 10.5
x= 20.5 (result var. x is must be float)
Explicit type conversion
It will be performed by the programmer. According to the need of this in the program.
Syntax: datatype (var) Eg: int y = 10;
float z = 2.5;(resultant type of y+z is float, that is converted explicitly to int type) x = int (y + z);
Now the result is of int type.
Constants
A quantity that does not change is known as constants.
Types of constants:
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Integer constants-
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-
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Eg: 123, 25
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Character constants
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- Eg: ‘A’, ‘B’, ‘*’, ‘1’
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Real constants
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-
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Eg: 12.3, 2.5
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- with decimal point
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Strings
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A sequence of characters is called string. String constants are enclosed in double quotes as follows
“Hello”
Operators
An operator is a symbol that tells the computer to perform certain mathematical or logical manipulations.