C Tutorial/Data Type/Data Type
Содержание
C Numeric Data Types
Keyword Variable Type Range
char Character (or string) -128 to 127
int Integer -32,768 to 32,767
short Short integer -32,768 to 32,767
short int Short integer -32,768 to 32,767
long Long integer -2,147,483,648 to 2,147,483,647
unsigned char Unsigned character 0 to 255
unsigned int Unsigned integer 0 to 65,535
unsigned short Unsigned short integer 0 to 65,535
unsigned long Unsigned long integer 0 to 4,294,967,295
float Single-precision +/-3.4E10^38 to +/-3.4E10^38
floating-point
(accurate to 7 digits)
double Double-precision +/-1.7E10^308 to +/-1.7E10^308
floating-point
(accurate to 15 digits)C has really only four types of variables:
- char
- int
- float
- double
Get maximum and minimum values of data type
#include <stdio.h>
main(){
int i,j ;
i = 1;
while (i > 0) {
j = i;
i++;
}
printf ("the maximum value of integer is %d\n",j);
printf ("the value of integer after overflow is %d\n",i);
}the maximum value of integer is 2147483647
the value of integer after overflow is -2147483648
Introduction to Data Types
- Data type determines how much storage space is allocated to variables.
- Data type determines the permissible operations on variables.
- The variables should be declared by specifying the data type.
- There is a family of integer data types and floating-point data types.
- Characters are stored internally as integers
- Characters are interpreted according to the character set.
- The most commonly used character set is ASCII.
- In the ASCII character set, A is represented by the number 65.
2.1.Data Type 2.1.1. <A href="/Tutorial/C/0040__Data-Type/Whatisadatatype.htm">What is a data type</a> 2.1.2. Introduction to Data Types 2.1.3. <A href="/Tutorial/C/0040__Data-Type/CNumericDataTypes.htm">C Numeric Data Types</a> 2.1.4. <A href="/Tutorial/C/0040__Data-Type/Useunsignedvariables.htm">Use unsigned variables</a> 2.1.5. <A href="/Tutorial/C/0040__Data-Type/SignedandUnsignedVariables.htm">Signed and Unsigned Variables</a> 2.1.6. <A href="/Tutorial/C/0040__Data-Type/Getmaximumandminimumvaluesofdatatype.htm">Get maximum and minimum values of data type</a> 2.1.7. <A href="/Tutorial/C/0040__Data-Type/Multipledeclarations.htm">Multiple declarations</a>
Multiple declarations
#include <stdio.h>
int main()
{
int m,y,d;
m = 1;
y = 2;
d = 3;
printf(" %d %d %d \n",m, y, d);
return 0;
}1 2 3
Signed and Unsigned Variables
Signed Range Unsigned Range
char -128 to 127 unsigned char 0 to 255
int -32768 to 32,767 unsigned int 0 to 65,535
long -2,147,483,648 unsigned long 0 to 4,294,967,295 to 2,147,483,647Use unsigned variables
When declaring a numeric variable in C, you can use "signed" or "unsigned".
Variable is signed unless you specifically type unsigned before the variable type:
unsigned int sh = 26;- The standard int variable can hold values from -32,768 up to 32,767.
- That"s half negative numbers, from -32,786 to -1, and then half positive numbers, from 0 up to 32,767.
- An unsigned number means that the variable holds only positive values.
- Your typical unsigned int has a range from 0 to 65,535.
What is a data type
For each variable you have to attach some data type.
The data type defines:
- the amount of storage allocated to variables.
- the values that they can accept.
- the operations that can be performed on variables.
2.1.Data Type 2.1.1. What is a data type 2.1.2. <A href="/Tutorial/C/0040__Data-Type/IntroductiontoDataTypes.htm">Introduction to Data Types</a> 2.1.3. <A href="/Tutorial/C/0040__Data-Type/CNumericDataTypes.htm">C Numeric Data Types</a> 2.1.4. <A href="/Tutorial/C/0040__Data-Type/Useunsignedvariables.htm">Use unsigned variables</a> 2.1.5. <A href="/Tutorial/C/0040__Data-Type/SignedandUnsignedVariables.htm">Signed and Unsigned Variables</a> 2.1.6. <A href="/Tutorial/C/0040__Data-Type/Getmaximumandminimumvaluesofdatatype.htm">Get maximum and minimum values of data type</a> 2.1.7. <A href="/Tutorial/C/0040__Data-Type/Multipledeclarations.htm">Multiple declarations</a>
