Loops

Repetition Structure in C++

What is Repetition Structure?  Repetition

Structure or loops permits a sequence of instructions to be executed repeatedly until a certain condition is reached.  Each pass of the loop is called iteration.  Loops comes in three forms: while, do-while and for.

Kinds of Loops  For

loop  While loop  Do-while loop

Importance of loops… #include main() { cout<<“Siena\n”; cout<<“Siena\n”; cout<<“Siena\n”; cout<<“Siena\n”; cout<<“Siena\n”; }



The program will show 5 siena’s on the screen. however, if you were ask to do the same program except this time you print siena 100 times, are you willing to type cout<< 100 times?

While loops Syntax: While (condition) { Statement1; Statement2; Statementn; }

Example: This program will print out the number from 1-5. #include main() { int ctr; ctr=1; while(ctr<=5) { cout<<“ \n”<
What is wrong in the program? Example: This program will print out the number from 1-5. #include main() { int ctr; ctr=1; while(ctr<=5) { cout<<“ \n”<
Do-while loops 

Syntax:



do{ Statement1; Statement2; Statementn; }while(condition);

Example: This program will print out all even nos. from 1-10. #include main() { int ctr; ctr=1; do{ cout<<“ \n”<
What do this program display? Example: This program will print out all even nos. from 1-10. #include main() { int ctr; ctr=1; do{ ++ctr; cout<<“ \n”<
While vs. Do-while  What

makes differ?

Example: This program will print out the number from 1-5. #include main() { int ctr; ctr=0; do{ ++ctr; cout<<“ \n”<
Example: This program will print out the number from 1-5. #include main() { int ctr; ctr=1; while(ctr<=5) { cout<<“ \n”<
For loops Syntax: for(initialization; condition; statement)

{ statement1; statement2; statementn; }

A program that will print all even numbers -from 0 – 10. #include main() { int ctr; for(ctr=0;ctr<=10;ctr+=2) { cout<
Solution… #include main() { int ctr; for(ctr=1;ctr<=5;++ctr) { cout<<“siena\n”; }

}

 Using

three kinds of loops, Create a program to display All ODD numbers from 0 -15 in decreasing order.  Ex: –

15 13 11 9 7 5 3 1