Switch and For Loop Explained using C Language.

2. Switch Statement
SYNTAX
switch(variable||constant||character)
{
case 1:
statement1;
statement2;
break;
case 2:
statements;
break;
.
.
default:
statements;
}

3. Example..
void main()
{
char ch=‘x’;
switch(ch)
{
case ’v’:
printf(“In case v ”);
break;
case ’a’:
printf(“In case a ”);
break;
case ’x’:
printf(“In case x ”);
break;
default:
printf(“I am in defaultn”);
}
}

4. •Switch statement can also contain Expressions
eg switch(i+j*k)
switch(45*j)
•Only constant expressions can be evaluated in
case
eg case 5+9 is correct.
case a+b is incorrect

5. Limitation of switch
• A float Expression cannot be tested using a switch.
• Multiple cases cannot use same expression values.
eg
switch(var)
{
case 6:
…………..
.
.
case 3*2:
}
It is an Illegal Expression
• case a>2: is an illegal expression

7. The Loop Control Structure
For Loop
While Loop
Do-While Loop

8. for Loop

9. for Loop
• Syntax
void main()
{
for(initialization; condition;increment/decrement)
{
statements;
}
}

10. for Loop
A Basic program:- Take 5 numbers from user and
find their sum.
void main()
{
int a,i,sum;
printf(“Enter Five number”);
for (i=0;i<5;i++)
{
scanf(“%d”,&a);
sum=sum+a; //
}
printf(“The sum is %d”,sum);
}

11. for Loop
Some more formats.
• void main()
{
int i;
for(i=1;i<=10;i=i+1)
printf(“%dn”,i);
}
• void main()
{
int i;
for(i=1;i<=10;)
{
printf(“%dn”,i);
i=i+1;
}
}

12. for Loop
Some more formats.
• void main()
{
int i=1;
for(;i<=10;i=i+1)
printf(“%dn”,i);
}
• void main()
{
int i=1;
for(;i<=10;)
{
printf(“%dn”,i);
i=i+1;
}
}

13. for Loop
Some more formats.
• void main()
{
int i;
for(i=0;i++<10;)
printf(“%dn”,i);
}
• void main()
{
int i;
for(i=0;++i<=10;)
{
printf(“%dn”,i);
}
}

14. Nested for loop
• 1*1
• 1*2
• 2*1
• 2*2
• 3*1
• 3*2

15. Nested for loop
void main()
{
int i,j;
for(i=1;i<4;i++)
{
for(j=1;j<=2;j++)
{
printf(“%dn”,i*j)
}
}

16. Multiple Initializations in for loop
• for(i=1,j=2;j<=10;j++,i++)

17. Break Statement

18. Break Statement
• main()
{
int num,i;
printf(“Enter a number”);
scanf(“%d”,&num);
i=2;
while(i<=num-1)
{
if(num%i==0)
{
printf(“Not a prime number”);
break;
}
i++;
}
if(i==num)
printf(“Prime number”);
}

19. Continue statement
void main()
{
int x;
for ( x = 1; x <= 10; x++ ) {
if ( x == 5 )
continue; /* skip remaining code in loop only if x == 5 */
printf( "%d ", x );
}
printf( "nUsed continue to skip printing the value 5n" );
}

20. Output

21. Predict the output:
void main()
{
float a=3;
switch(a)
{
case 1:
printf(“Value is 1”);
break;
case 2:
printf(“Value is 2”);
break;
case 3:
printf(“Value is 3”);
break;
default:
printf(“ERROR!!”);
}
}

22. Predict the output
void main(){
int x=0,y=0,i,j;
for(i=0;i<2;i++);
for(j=1;j<3;j++)
{
x++;
}
y++;
printf("x: %d, y: %d",x,y);
getch();
}

23. Predict the output..
• void main(){
• int ch='a'+'b';
• printf("%cn",ch);
• switch(ch)
• {
• case 'a':
• case 'b':
• printf("u entered bn");
• case 'A':
• printf("u entered An");
• case 'b'+'a':
• printf("u entered b and an");
• default:
• printf("Reached default");
• }
• }

25. Output???
• void main()
{
char ch='a';
printf("%d",ch);
}

26. Output????
• 97
void main()
{
int ch=3;
printf(“%c”,ch);
}

27. Ans ♥

28. Output????
void main()
{
char c=1;
switch(c)
{
case '1':
printf("In '1'");
break;
case 1||2:
printf(" In 1 or 2");
break;
default:
printf("Not found");
}
}

29. • ANS
• In 1 or 2

30. Output???
void main()
{
int suite=1;
switch(suite);
{
case 0;
printf("Clubn");
case 1;
printf("Diamondn");
}
}

31. Output

32. Output????
void main()
{
switch('A'+1)
{
case 66:
printf("In 66");
break;
case 1+'A':
printf("In same") ;
break;
case 'B':
printf("In B") ;
break;
default:
printf("In default");
break;
}
}