Code from lecture

https://github.com/ucsb-cs16-s18-mirza/cs16-s18-lectures/tree/master/lec-03

Topics

Github intro

• What is github? How and why we plan to use it in this class
• What is a git repo?
• Creating a github repo and using github’s web interface to store your first program
• Basics - organization, repos
• Using github’s web interface
  • creating a repo
  • adding files to the repo
  • adding collaborators to the repo
  • updating files and viewing the version history

• Show command line usage - but won’t go into too much detail

• Intro to lab01
• For loops are DIFFERENT in C++ than in Python. We’ll discuss.
• Simple accumulator
• For loops, applied to a simple accumulator pattern (find sum of a series)

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

Exercise: Write a program to draw a square of a given width Example usage:

$./drawSquare 
Enter the width of the square: 5
* * * * *
* * * * *
* * * * *
* * * * *
* * * * *

Complete the code below

#include <iostream>
using namespace std;

void drawSquare(int n); // Function to draw a square of side n

int main(){
  // Complete the code below:
  
  
  cout<<"Enter the width of the square : "
  cin>> num;
    
}

// Write the definition of a function drawSquare that takes one parameter
void drawSquare(int n){













}

Exercise: Write a program to draw a triangle of a given width Example usage:

$./drawTriangle
Enter the width of the triangle: 5
* * * * *
* * * * *
* * * * *
* * * * *
* * * * *

Complete the code below

#include <iostream>
using namespace std;

void drawTriangle(int n); // Function to draw a triangle of side n

int main(){
  // Complete the code below:
  
  
  cout<<"Enter the width of the triangle : "
  cin>> num;
  
  
}

// Which line of code do you need to modify
void drawTriangle(int n){
  for(int j = 0 ; j < n; j++){   //A
    for(int i = 0 ; j < n; j++){ //B
      cout<<"* ";  //C
    }
    cout<<endl;    //D
  }
  cout<<endl;      //E
}

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.