55 data types main int a b c sum a 1 b 2 c 3 sum a b

55
Data types
main( ) { int a, b, c, sum;
a = 1; b = 2; c = 3;
sum = a + b + c;
printf("sum is %d", sum);
}
main( ) { int a, b;
float c, sum;
a = 1; b = 2; c = 3.5;
sum = a + b + c;
printf("sum is %f", sum);
}

56
Numeric data types
l
char
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Individual characters (Range 127 to -128)
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int
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Integers
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Short
(-65536 to 65535) or
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Long
-2,147,483,648 to 2,147,483,647
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float
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Real numbers 3.4 E +/- 38 (32 bits long)
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double
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Real numbers with double precision 3.4 E +/- 308 (64 bits long)
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Modifiers
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Short (16 bit), long (32bit)
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Control the range of numbers
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signed, unsigned
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for integers and whole numbers respectively

57
Arithmetic Operators
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Symbol Operation Usage
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* multiply x * y
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/ divide x / y
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% modulo x % y
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+ addition x + y
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- subtraction x - y
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All associate left to right.
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* / % have higher precedence than + - .

58
Special Operators: ++ and --
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Changes value of variable before (or after)
its value is used in an expression.
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Symbol Operation Usage
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++ postincrement x++
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-- postdecrement x--
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++ preincrement ++x
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<= predecrement --x
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Pre : Increment/decrement variable before using its value.
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Post : Increment/decrement variable after using its value.

@2012
Badri Nath
Computer Architecture
211
59
Examples
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#include <stdio.h>
#include <stdlib.h>
int main()
{
char weight[4];
int w;
w=140;
printf("Here is what you weigh now: %i\n",w);
w--;
printf("w--: %i\n",w);
w++;
printf( “ ++w: %i\n",w);
printf ( “ pre DECR %i \n ” , --w);
printf ( “ post INCR %i \n ” , w++);
printf ( “ value of w %i \n ” , w);
return(0);
}
#include<stdio.h>
main( )
{
int i = 3, j = 4,k;
k = i++ + --j;
printf("i = %d, j = %d, k = %d",i,j,k);
}

60
Relational Operators
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Symbol Operation Usage
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> greater than x > y
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>= greater than or equal x >= y
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< less than x < y
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<= less than or equal x <= y
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== equal x == y
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!= not equal x != y
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Result is 1 (TRUE) or 0 (FALSE).
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Note : Don't confuse equality (==) with assignment (=).

61
Logic Operators
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Symbol Operation Usage
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! logical NOT !x
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&& logical AND x && y
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|| logical OR x || y
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Treats entire variable (or value) as TRUE
(non-zero) or FALSE (zero).
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Result is 1 (TRUE) or 0 (FALSE).

62
Bit operators
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In C, there are operators that work on bits of a word
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& logical AND
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| inclusive OR
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~ NOT
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Example
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x = 8 y = 7
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x& y
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x | y
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! X
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E.g., 72 & 184 = 8 ; 72 | 184 = 248 ;

@2012
Badri Nath
Computer Architecture
211
63
Variable Declarations
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Variables are used as names for
data items.
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Each variable has a type ,
which tells the compiler how the
data is to be interpreted (and how
much space it needs, etc.).
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int counter;
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int
startPoint;
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Float pi=3.14;
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int is a predefined
integer type in C.
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#include <stdio.h>
int main()
{
int pints=1;
float price = 1.45;
printf("You want %d
pint.\n",pints);
printf("That be $
%f, please.\n “ , price);
return(0);
}

64
Control Structures
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Same control structures as Java. Same syntax
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Conditional
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if
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if-else
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switch
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Iteration
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while
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for
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do-while
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also has the break and continue expressions.

65
Control Structures
l
Same control structures as Java. Same syntax
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Conditional
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if
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if-else
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switch
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Iteration
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while
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for
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do-while
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also has the break and continue expressions.