This document is a tutorial on programming loops in C programming language. It discusses the need for loops, different types of looping statements like while, for, do-while loops. It provides examples of using these loops and some practice problems to help understand loops better. The document is written by Yogendra Pal and dedicated to his parents. It encourages the reader to solve mind exercises, ask questions, and watch tutorials to keep learning C programming.

1. C Programming
Language
By:
Yogendra Pal
yogendra@learnbywatch.com
Dedicated to My mother and Father

2. t
y
Keep your notebook with you.
Write important point and questions that comes in your mind
Solve Mind band exercise.
C
Rewind when not clear
Ask Questions by call or SMS or by mail
Keep Watching Keep Learning
THIS IS LOOPS
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3. Need
• Consider a problem:
– Write a program that print “Hello” 5 times.
– One possible statement to solve this problem is :
• printf(“Hello n Hello n Hello n Hello n Hello);
– But what if we want to print “Hello” 1000 times?
– We need a control structure that repeatedly execute
the following statement.
• printf(“n Hello);

4. Decision statements
• To change the control flow of a program we
use:
– Branching statements : cause one section of code
to be executed or not executed, depending on a
conditional clause.
– Looping statements : used to repeat a section of
code a number of times or until some condition
occurs.

5. Looping Statements
• Allow the program to repeat a section of code
any number of times untill some condition
occures.

6. Looping statements : 1
• while statement
initial_statement;
– General form: while(condition){
statement;
while(condition) iteration_statement;
statement; }
• The program will repeatedly execute the
statement inside the while until the condition
becomes false (0)

7. Problems
• Write a program that print “Hello” 5 times.
while(counter <= 5)
printf(“Hello”);
• This statement reads
– “while counter is less than or equal to 5 print Hello ”

8. Multiple Statements
• Put all statements inside the curly { } braces.
while(condition)
{
statement 1;
statement 2;
statement 3;
}

9. (I ++) or (++ I)
• while (i++ < 10)
– compare i with 10,
– increment i.
• while (++i < 10)
– increment i,
– compare i with 10.

10. Problems
• Write a program that print numbers from 1 to 100.
• Write a program that print sum of 10 consecutive
numbers, enter first number using keyboard.
• Write a program that print all even numbers from
1 to 100.
• Write a program to find the factorial value of any
number entered through the keyboard.

11. break statement
• break statement:
– Loops can be exited at any point through the use of
a break statement.
• Write a program that checks whether a given
number is prime of not.

12. continue statement
• continue statement:
– continue starts re-executing the body of the loop
from the top.
• Write a program that print numbers from 1 to 100
except the numbers that are divisible by 5 using
continue statement.

13. Nested while
while(condition) while(condition)
while(condition) {
statement; while(condition)
{
statement;
while(condition) }
{ }
if(condition)
statement;
else
statement;
}

14. Mind Bend
Write a program that print all the numbers
from 2 to 100 with the indication whether a
number is prime of not.
Output will be like:
2 : prime
3 : prime
4 : not prime

15. Looping Statement : 2
• for statement
• General form:
for (initial_statement; condition; iteration_statement)
body_statement;
initial_statement;
while(condition){
statement;
iteration_statement;
}

16. Problems
• Two numbers (x and y) are entered through
the keyboard. Write a program to find the
value of xy
• Write a program that print numbers from 1
to 100 except the numbers that are divisible
by 5 and 7.
• Write a program to print all characters with
their ASCII value.
16

17. Looping Statement : 3
• do-while loop
do{
statement1;
statement2
}while(condition)
• do-while run the statements at least once.

18. Problems
• Write a program that first take two numbers
from user and then one operator (+, -, *, /, %)
and print the result accordingly.
• Now modify the above program that give an
option to the user to repeat the operation
again and again with different operator
choosen by him.

19. Mind Bend
• Write a program that takes 10 floating-point
numbers as a input from user and print the
greatest number.
• Write a program that take floating point
number from user and print
– ICE if it is less than 0.
– WATER if it lies between 0 and 100.
– STEAM if it is greater then 100.
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20. To get complete benefit of this tutorial solve all the quiz on
www.learnbywatch.com
For any problem in this tutorial mail me at
yogendra@learnbywatch.com
with the subject “C”
For Other information mail at
info@learnbywatch.com
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NEXT IS FUNCTIONS
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