Counting Loops

for Syntax for (expression1; expression2; expression3)     statement

for Syntax for (expression1; expression2; expression3)     statement

for Syntax for (expression1; expression2; expression3)     statement

for Syntax for (expression1; expression2; expression3)     statement

for Syntax for (expression1; expression2; expression3)     statement

for Syntax for (expression1; expression2; expression3)     statement

Bad Form cout << “What is 2+2? ”; cin >> sum; for (; sum != 4;) { cout << “Incorrect answer. What is 2+2? ” << endl; cin >> sum; }

Example #1 float average; long sum = 0; short i = 0; cout << “enter positive integer: ”; cin >> max; for(i=0; i <= max; i++)   sum += i; average = static_cast<float>(sum) / max; cout << “average is ” << average << endl;

Example #1 float average; long sum = 0; short i = 0; cout << “enter positive integer: ”; cin >> max; for(i=0; i <= max; i++)   sum += i; average = static_cast<float>(sum) / max; cout << “average is ” << average << endl;

Example #1 float average; long sum = 0; short i = 0; cout << “enter positive integer: ”; cin >> max; for(i=0; i <= max; i++)   sum += i; average = static_cast<float>(sum) / max; cout << “average is ” << average << endl;

Example #1 float average; long sum = 0; short i = 0; cout << “enter positive integer: ”; cin >> max; for(i=0; i <= max; i++)   sum += i; average = static_cast<float>(sum) / max; cout << “average is ” << average << endl;

Example #2 float average; long sum = 0; short i = 0; cout << “enter positive integer: ”; cin >> max; for (i=0; i <= max; i+=2)   sum += i; average = static_cast<float>(sum) / max; cout << “average is ” << average << endl;

Goal Output * * * * * * * * * * * * * * *

Outputting 5 Lines for (int i = 1; i <= 5; i++) {   cout << endl; }

Outputting 5 Stars for (int i = 1; i <= 5; i++) {   cout << “* ”; }

Combining for (int i = 1; i <= 5; i++) {    for (int j = 1; j <= 5; j++)         cout << "* ";                           cout << endl; } output variable values i=1 j=?

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values i=1 j=1

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * i=1 j=1

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * i=1 j=2

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * i=1 j=2

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * i=1 j=3

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * i=1 j=3

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * i=1 j=4

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * i=1 j=4

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * i=1 j=5

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * i=1 j=5

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * i=1 j=6

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * i=1 j=6

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * i=2 j=?

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * i=2 j=1

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * i=2 j=1

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * i=2 j=2

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * i=2 j=2

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * i=2 j=3

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * i=2 j=3

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * i=2 j=4

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * i=2 j=4

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * i=2 j=5

Combining for (int i = 1; i <= 5; i++) {     for (int j = 1; j <= 5; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * i=2 j=5 oops!!!

Goal vs Actual Goal * * * * * * * * * * * * * * * Actual * * * * * * * * * * * * * * * Actual * * * * * * * * * * * * * * * * * * * * * * * * * i=1 i=2 j=5 i=3 j=4 i=4 j=3 i=5 j=2 j=1

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values i=1 j=?

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values i=1 j=1

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * i=1 j=1

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * i=1 j=2

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * i=1 j=2

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * i=1 j=3

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * i=1 j=3

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * i=1 j=4

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * i=1 j=4

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * i=1 j=5

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * i=1 j=5

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * i=1 j=6

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * i=1 j=6

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * i=2 j=?

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * i=2 j=1

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * i=2 j=1

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * i=2 j=2

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * i=2 j=2

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * i=2 j=3

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * i=2 j=3

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * i=2 j=4

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * i=2 j=4

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * i=2 j=5

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * i=2 j=5

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * i=3 j=?

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * i=3 j=1

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * i=3 j=1

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * i=3 j=2

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * i=3 j=2

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * i=3 j=3

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * i=3 j=3

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * i=3 j=4

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * i=3 j=4

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * i=4 j=?

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * i=4 j=1

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * i=4 j=1

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * i=4 j=2

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * * i=4 j=2

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * * i=4 j=3

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * * i=4 j=3

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * * i=5 j=?

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * * i=5 j=1

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * * * i=5 j=1

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * * * i=5 j=2

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * * * i=5 j=2

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * * * i=6 j=?

Fixed for (int i=1; i <= 5; i++) {     for (int j=1; j <= 5 – i + 1; j++)           cout << "* ";                           cout << endl; } output variable values * * * * * * * * * * * * * * * i=6 j=?

Goal Output * * * * * * * * * * * * * * *

Solution Rows * * * * * * * * * * * * * * * for (short i = 0; i < 5; i++) {     for (short j = 1; j <= i; j++)         cout << " ";     for (short j = i; j < 5; j++)         cout << "* ";     cout << endl; } * * * * * * * * * * * * * * *

Solution Spaces * * * * * * * * * * * * * * * for (short i = 0; i < 5; i++) {     for (short j = 1; j <= i; j++)         cout << " ";     for (short j = i; j < 5; j++)         cout << "* ";     cout << endl; } * * * * * * * * * * * * * * *

Solution Stars * * * * * * * * * * * * * * * for (short i = 0; i < 5; i++) {     for (short j = 1; j <= i; j++)         cout << " ";     for (short j = i; j < 5; j++)         cout << "* ";     cout << endl; } * * * * * * * * * * * * * * *

Out of Scope for (int i = 1; i <= 10; i++)   cout << “hello” << endl; cout << i << endl;

Out of Scope for (int i = 1; i <= 10; i++) {   cout << “hello” << endl; } cout << i << endl;

Fixed Scope int main() { int i; for (i = 1; i <= 10; i++) {      cout << “hello” << endl; } cout << i << endl; return 0; }

Duplicate Variables int main() { int i = 20; for (int i =1; i <= 10; i++) {      cout << “hello” << endl; } cout << i << endl; return 0; }

End of Session