The document discusses different types of control statements in C programming including decision control statements, iteration statements, and transfer statements. It provides details about if, if-else, switch, while, do-while, for loops. Decision control statements like if, if-else, switch allow altering the flow of execution based on certain conditions. Iteration statements like while, do-while, for are used to repeat a block of code until the given condition is true. They allow looping in a program.

2. Decision
control
statement
Iteration
statement
Transfer
statement

3. Decision Control statement:-
Decision
control
statement
Decision control statement disrupt or alter the
sequential execution of the statement of the program
depending on the test condition in program
Types of Decision control statement:-
1. If
statement
3. Switch
statement
4. Go To
statement
2. If else
statement

4. The If statement is a powerful
decision making statement
and is used to control the flow
of execution of statement.condition
Block of if
Next statement
STOP
FALSE
TRUE

5. main()
{
int a;
printf(“enter value of a”);
scanf(“%d”,&a);
if(a>25)
{
}
printf(“no.is greater than 25”);
printf(“n bye”);
}

6. condition
Block of if
Next statement
STOP
FALSE
TRUE
Block of else
If the condition is true the true block is execute
otherwise
False block is execute.

7. main()
{
int n,c;
printf(“n enter value of n”);
scanf(“%d”,&n);
c=n%2;
if(c==0)
printf(“no is even”);
else
printf(“no is odd”);
getch();
}

8. What Is Else If Ladder:
If we are having different - different test conditions with different - different statements,
then for these kind of programming we need else if ladder
Syntax Of Else If Leader:
---------------------------------------------------------------------
if(test_condition1)
{
statement 1;
}
else if(test_condition2)
{
statement 2;
}
else if(test_condition3)
{
statement 3;
}
else if(test_condition4)
{
statement 4;
}
else
{
}

9. void main ( )
{
int num = 10 ;
if ( num > 0 )
printf ("n Number is Positive");
else if ( num < 0 )
printf ("n Number is Negative");
else printf ("n Number is Zero");
}

10. Switch statement is a multi-way decision making statement which selects one
of the several alternative based on the value of integer variable or expression.
A switch statement tests the value of a variable and compares it with multiple
cases. Once the case match is found, a block of statements associated with that
particular case is executed.
Each case in a block of a switch has a different name/number which is referred to
as an identifier. The value provided by the user is compared with all the cases
inside the switch block until the match is found.
. Syntax :-
switch(expression)
{
case constant 1: statement;
break;
case constant 2: statement;
break;
default : statement;
}

11. Flow Chart Diagram of Switch Case
Following diagram illustrates how a case is selected in switch case:

12. #include <stdio.h>
int main() {
int num = 8;
switch (num) {
case 7:
printf("Value is 7");
break;
case 8:
printf("Value is 8");
break;
case 9:
printf("Value is 9");
break;
default:
printf("Out of range");
break;
}
return 0;
}
Output:
Value is 8
Example
Following program illustrates the use of switch:

13. #include <stdio.h>
int main() {
int language = 10;
switch (language) {
case 1:
printf("C#n");
break;
case 2:
printf("Cn");
break;
case 3:
printf("C++n");
break;
default:
printf("Other programming languagen");}}
Output:
Other programming language
Example:

14. main()
{
char choice;
printf(“enter any alphabet”);
scanf(“%d”,& choice);
switch(choice)
{
case ‘a’:
printf(“this is a vowel n”);
break;
case ‘e’ :
printf(“this is a vowel n”);
break;
case ‘i’ :
printf(“this is a vowel n”);
break;
case ‘o’ :
printf(“this is a vowel n”);
break;
case ‘u’ :
printf(“this is a vowel n”);
break;
default :
printf(“this is not a vowel”);
}
}

15. #include<stdio.h>
void main( )
{
int a, b, c, choice;
/* Printing the available options */
printf("n 1. Press 1 for addition");
printf("n 2. Press 2 for subtraction");
printf("n Enter your choice");
/* Taking users input */
scanf("%d", &choice);
switch(choice)
{
case 1:
printf("Enter 2 numbers");
scanf("%d%d", &a, &b);
c = a + b;
printf("%d", c);
break;
Example

16. case 2:
printf("Enter 2 numbers");
scanf("%d%d", &a, &b);
c = a - b;
printf("%d", c);
break;
default:
printf("you have passed a wrong key");
printf("n press any key to continue");
}
}

17. In switch case, the break statement is used to terminate the switch case.
Basically it is used to execute the statements of a single case statement. If no
break appears, the flow of control will fall through all the subsequent cases
until a break is reached or the closing curly brace ‘}’ is reached.
#include <stdio.h>
int main()
{
int i=2;
switch (i)
{
case 1:
printf("Case1 ");
case 2:
printf("Case2 ");
case 3:
printf("Case3 ");
case 4:
printf("Case4 ");
default:
printf("Default ");
}
return 0;
}
Output:
Case2 Case3 Case4 Default

18. CONDITIONAL OR TERNARY OPERATORS IN C:
Conditional operators return one value if condition is true and returns
another value is condition is false.
This operator is also called as ternary operator.
Syntax : (Condition? true_value: false_value);
Example : (A > 100 ? 0 : 1);
In above example, if A is greater than 100, 0 is returned else 1 is
returned. This is equal to if else conditional statements.

19. Loop control statements in C are used to perform looping operations until
the given condition is true. Control comes out of the loop statements once
condition becomes false.
Sometimes we want some part of our code to be executed more than once.
We can either repeat the code in our program or use loops instead. It is
obvious that if for example we need to execute some part of code for a
hundred times it is not practical to repeat the code. Alternatively we can
use our repeating code inside a loop.

20. • Depending on the position of control statement in c,control structure may
be classified in
• Entry_ controlled loop (Top Tested)
In an entry controlled loop, a condition is checked before executing the body
of a loop. It is also called as a pre-checking loop.
Exit _controlled loop (Bottom Tested)
In an exit controlled loop, a condition is checked after executing the body of
a loop. It is also called as a post-checking loop.

21. False
Entry controlled loop exit controlled loop
Test
conditio
n ?
true
Body of the
loop
Body of the
loop
Test
conditio
n ?

22. • C language provides three constructs for
perfoming loop operations
• While statement
• Do statements
• For statements

24. While(test condition)
{
body of the loop
}

25. #include <stdio.h>
int main()
{
int count=1;
while (count <= 4)
{
printf("%d ", count);
count++;
}
return 0;
}
Output:
1 2 3 4

26. ………………………
………………………
int sum=0;
int n=1;
while(n<=10)
{
sum=sum+n;
n=n+1;
}
printf(“sum=%dn”, sum);
…………………………………………..

27. #include <stdio.h>
int main () {
/* local variable definition */
int a = 10;
/* while loop execution */
while( a < 20 ) {
printf("value of a: %dn", a);
a++;
}
return 0;
}
When the above code is compiled and executed, it
produces the following result −
value of a: 10
value of a: 11
value of a: 12
value of a: 13
value of a: 14
value of a: 15
value of a: 16
value of a: 17
value of a: 18
value of a: 19

28. A do while loop is similar to while loop with one exception that it
executes the statements inside the body of do-while before checking
the condition. On the other hand in the while loop, first the
condition is checked and then the statements in while loop are
executed. So you can say that if a condition is false at the first place
then the do while would run once, however the while loop would
not run at all.

29. Do statement
do
{
Body of the loop
}
While(test condition)

30. #include <stdio.h>
int main()
{
int j=0;
do
{
printf("Value of variable j is: %dn", j);
j++;
}while (j<=3);
return 0;
}
Output:
Value of variable j is: 0
Value of variable j is: 1
Value of variable j is: 2
Value of variable j is: 3

31. #include<stdio.h>
#include<conio.h>
int main()
{
int num=1; //initializing the variable
do //do-while loop
{
printf("%dn",2*num);
num++; //incrementing operation
}while(num<=10);
return 0;
}
Output:
2
4
6
8
10
12
14
16
18
20

32. While vs do..while loop in C
Using while loop:
#include <stdio.h>
int main()
{
int i=0;
while(i==1)
{
printf("while vs do-while");
}
printf("Out of loop");
}
Output:
Out of loop

33. Same example using do-while loop
#include <stdio.h>
int main()
{
int i=0;
do
{
printf("while vs do-whilen");
}while(i==1);
printf("Out of loop");
}
Output:
while vs do-while
Out of loop

34. For statements
For(intialization;testcondition;icrement)
{
body of the loop
}

35. A for loop is a repetition control structure that allows you to
efficiently write a loop that needs to execute a specific number
of times.
Syntax
The syntax of a for loop in C programming language is −
for ( init; condition; increment )
{
statement(s);
}

37. Step 1: First initialization happens and the counter variable gets
initialized.
Step 2: In the second step the condition is checked, where the
counter variable is tested for the given condition, if the
condition returns true then the C statements inside the body of
for loop gets executed, if the condition returns false then the
for loop gets terminated and the control comes out of the loop.
Step 3: After successful execution of statements inside the
body of loop, the counter variable is incremented or
decremented, depending on the operation (++ or –).

38. Example of For loop
#include <stdio.h>
int main()
{
int i;
for (i=1; i<=3; i++)
{
printf("%dn", i);
}
return 0;
}
Output:
1
2
3

39. // Program to calculate the sum of first n natural numbers
// Positive integers 1,2,3...n are known as natural numbers
#include <stdio.h>
int main()
{
int num, count, sum = 0;
printf("Enter a positive integer: ");
scanf("%d", &num);
// for loop terminates when num is less than count
for(count = 1; count <= num; ++count)
{
sum += count;
}
printf("Sum = %d", sum);
return 0;
Output
Enter a positive integer: 10
Sum = 55

40. C Program: Print table for the given number using C for loop
#include<stdio.h>
int main(){
int i=1,number=0;
printf("Enter a number: ");
scanf("%d",&number);
for(i=1;i<=10;i++){
printf("%d n",(number*i));
}
return 0;
}
Output
Enter a number: 2
2
4
6
8
10
12
14
16
18
20

41. Program to print natural numbers in reverse
#include <stdio.h>
int main()
{
int i, start;
/* Input start range from user */
printf("Enter starting value: ");
scanf("%d", &start);
/*
* Run loop from 'start' to 1 and
* decrement 1 in each iteration
*/
for(i=start; i>=1; i--)
{
printf("%dn", i);
}
return 0;
}

42. Program to print natural number in reverse in given range
#include <stdio.h>
int main()
{
int i, start, end;
/* Input start and end limit from user */
printf("Enter starting value: ");
scanf("%d", &start);
printf("Enter end value: ");
scanf("%d", &end);
/*
* Run loop from 'start' to 'end' and
* decrement by 1 in each iteration
*/
for(i=start; i>=end; i--)
{
printf("%dn", i);
}
return 0;
}

43. we can skip the initial value expression, condition and/or increment by adding a semicolon.
For example:
int i=0;
int max = 10;
for (; i < max; i++)
{
printf("%dn", i);
}
for(num=10;num<20;)
{
//Statements
num++;
}

44. Nesting of for loop
For(i=0;i<n;i++)
{
………………………………
For(j=0;j<n-1;j++)
{
………………………………
}
}
C programming allows to use one loop inside another loop.

45. #include <stdio.h>
int main()
{
for (int i=0; i<2; i++)
{
for (int j=0; j<4; j++)
{
printf("%d, %dn",i ,j);
}
}
return 0;
}
Output:
0, 0
0, 1
0, 2
0, 3
1, 0
1, 1
1, 2
1, 3

46. Skipping a part of loop
The continue statement is used inside loops. When a continue statement is
encountered inside a loop, control jumps to the beginning of the loop for
next iteration, skipping the execution of statements inside the body of loop
for the current iteration.
Eg:
While (test condition)
{
………………………..
If(…………)
Continue;

47. #include <stdio.h>
int main()
{
for (int j=0; j<=8; j++)
{
if (j==4)
{
/* The continue statement is encountered when
* the value of j is equal to 4.
*/
continue;
}
/* This print statement would not execute for the
* loop iteration where j ==4 because in that case
* this statement would be skipped.
*/
printf("%d ", j);
}
return 0;
}
Output:
0 1 2 3 5 6 7 8

48. Go To statement
A GO TO statement can cause program control to end up anywhere in the
program unconditionally.
Example :-
main()
{
int i=1;
up : printf(“Hello ToC”)
i++;
If (i<=5)
goto up
getch();
}

49. #include <stdio.h>
int main()
{
int sum=0;
for(int i = 0; i<=10; i++){
sum = sum+i;
if(i==5){
goto addition;
}
}
addition:
printf("%d", sum);
return 0;
}
Output:
15