Lecture 3, Mon 04/06

Loops (for, while, do-while), doubles, functions

Lecture Video

In two parts today because I forgot to talk about function declarations!

• Part 1: https://youtu.be/nj_KMp_zh2w
• Part 2: https://youtu.be/bW_mHZUJc5s

Topics

Working with doubles

• Evaluating expressions with mixed numeric types
• Typecasting int to double
• Formatted output with doubles:

Comment each line of code. What is the output of the code?

int i = 10;
double j = 1/static_cast<double>(i);
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(3);
cout<<j<<endl;

Practice with single for loops

• Summing a series:

Exercise: Write a program that takes a parameter n as a command line arguments and computes the following:

1 + 1/2 + 1/3 + ....+ 1/n

where n is the number of terms in the series. Sample run of the program is below:

$./sumSeries 2
Sum of the first 2 terms is: 1.500

Nested Loops

ASCII Art with nested loops

Math Puzzle

One of the powers of computing is being able to do a brute-force search for a solution to a problem. Trial and error works just fine for some problems. In fact, computers can be especially good at such problems. Consider this:

Horses cost $10, pigs cost $3, and rabbits are only $0.50. A farmer buys 100 animals for $100, How many of each animal did he buy?

Write a program to do this.