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2010-05-25T14:20:56Z

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==A free-standing block statement==

<source lang="cpp">
#include <stdio.h>
int main(void)
{
int i;
{
i = 1;
printf("%d", i);
}
return 0;
}

</source>

==Assign value to global variable==

<source lang="cpp">
#include <stdio.h>
int count;
int main(void)
{
extern int count; /* this refers to global count */
count = 10;
printf("%d", count);
return 0;
}

</source>

==Define and use global variable and function==

<source lang="cpp">
#include <stdio.h>
int i =0; //Global variable
void f1(void) {
int k; // local variable for f1.
i = 50;
}

main() {

int j; // local variable in main

f1();

i =0;

printf(" i in main %d\n",i);
f1();

printf(" i after call%d\n",i);
}

</source>

==Define and use Global variables==

<source lang="cpp">
#include <stdio.h>
int count = 0; /* Declare a global variable */
/* Function prototypes */
void test1(void);
void test2(void);
void main()
{
int count = 0; /* This hides the global count */
for( ; count < 5; count++)
{
test1();
test2();
}
}
/* Function test1 using the global variable */
void test1(void)
{
printf("\ntest1 count = %d ", ++count);
}
/* Function test2 using a static variable variable */
void test2(void)
{
static int count; /* This hides the global count */
printf("\ntest2 count = %d ", ++count);
}

</source>

==Define block inside a function==

<source lang="cpp">

#include <stdio.h>
main() {
int i = 10;

{
int i = 0;
for( i=0;i<2;i++) {
printf("i = %d\n",i);
}
}
printf("i = %d\n",i);
}

</source>

==Define local variable for a function==

<source lang="cpp">
int i =0; //Global variable
void f(void);
main() {
int i ; // local variable for main
i =0;

printf("value of i in main %d\n",i);

f();

printf("value of i after call%d\n",i);
}
void f(void) {
int i=0; //local variable for f
i = 50;
}

</source>

==Define variable in a block==

<source lang="cpp">

#include <stdio.h>
main() {
int k = 10;
int i = 100;
{
int i;
for(i = 0; i < 2; i++ ) {
printf("i = %d\n",i);
}
}
printf("i = %d\n",i);
}

</source>

==Global variable and function==

<source lang="cpp">
#include <stdio.h>
int count; /* count is global */
void func1(void);
void func2(void);
int main(void)
{
count = 100;
func1();
return 0;
}
void func1(void)
{
int temp;
temp = count;
func2();
printf("count is %d", count); /* will print 100 */
}
void func2(void)
{
int count;
for(count=1; count<10; count++)
putchar(".");
}

</source>

==Our own power function with parameters==

<source lang="cpp">

#include <stdio.h>
int power(int m, int e);
int main(void)
{
int m, e;
m = 3;
e = 4;
printf("%d to the %d is %d\n", m, e, power(m, e));
printf("5 to the 6th is %d\n", power(5, 6));
printf("4 to the 4rd is %d\n", power(4, 4));
return 0;
}
/* Parameterized version of power. */
int power(int m, int e)
{
int temp;
temp = 1;
for( ; e > 0; e--)
temp = temp * m;
return temp;
}

</source>

==Use global variable in function==

<source lang="cpp">

#include <stdio.h>
int max; /* a global variable */
void f(void)
{
int i;
for(i=0; i<max; i++)
printf("%d ", i);
}

int main(void)
{
max = 10;
f();
return 0;
}

</source>

==use global vars ==

<source lang="cpp">

#include <stdio.h>
/* global definition of first and last */
int first = 10, last = 20;
int main(void)
{
extern int first, last;
printf("%d %d", first, last);
return 0;
}

</source>

==Variable scope: in and out a block==

<source lang="cpp">

#include <stdio.h>
void main()
{
int c = 0; /* Declared in outer block */
do
{
int c = 0; /* This is another variable called c */
++c ; /* this applies to inner c */
printf("\n c = %d ", c );
}
while( ++c <= 3 ); /* This works with outer c */
/* Inner c is dead, this is outer */
printf("\n c = %d\n", c );
}

</source>

==Variable scope:inside a function==

<source lang="cpp">
#include <stdio.h>
int main(void)
{
int x;
x = 10;
if(x == 10) {
int x; /* this x hides the outer x */
x = 99;
printf("Inner x: %d\n", x);
}
printf("Outer x: %d\n", x);
return 0;
}

</source>

==Work with global variable==

<source lang="cpp">
#include <stdio.h>
int sample;
int main(void)
{
printf("%p", &sample);
return 0;
}

</source>

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