1. Lab 2
Variables in C

2. Variables in C Character (one byte) Integer (2 bytes)
char u;
Integer (2 bytes)
int a;
Long Integer (4 bytes)
long int a;
Float (4 bytes)
float x;
Double (8 bytes)
double z;

3. Variable Naming (Identifiers)
Variable name includes:
Letters a…z, A…Z
Numbers 0…9
Underscore _
First character either letters (a…z, A…Z) or underscore ( _ )
Variable name doesn’t include:
Spaces
Other characters ! : # …
Reserved names (int, float, void … etc)
A ≠ a

4. printf("format_string", argument_list);
Printing Variables
printf("format_string", argument_list);
int a=898;
float x= ;
printf("%d %f\n", a, x);
printf("a=%d x=%f\n", a, x);
a=898 x=

5. Conversion Specification
printf("a=%5d",a);
printf("x=%6.2f",x);
Field width
a= 898
x=126.65 8 9
.Precision
Field width 5 6 . 2 1

6. General Display Format
% [flag] [field width] . [precision]
Total=
%6.3f
%7.3f
%-7.3
99.123

7. Examples /* Lab2, student name, student ID */ #include <stdio.h>
Void main(void) {
int i; float x; double y; char q; // declaration
i=325; x=345.65; y= ; q=‘G’; // intialization
Printf(“i=%d\ni=%5d\ni=%-5d\ni=%+5d\ni=%0d\n”,i,i,i,i,i);
Printf(“\nx=%f\nx=%e\nx=%15.2e\nx=%15.4e\n”,x,x,x,x);
Printf(“\ny=%lf\ny=%le\nq=%c\n”,y,y,q); }