Perfect square. #include<iostream> using namespace std; int main(){ int a=1; int square; while(true){ } cout<<square<<endl; }

Transcription

1 Lab 3 Kaikai Bian

2 Perfect square #include<iostream> using namespace std; int main(){ int a=1; int square; while(true){ } cout<<square<<endl; }

3 Perfect square - Find and print the first perfect square (i*i) whose last two digits are both odd. - The first perfect square I got from my program is Why do I get negative number?

4 int The size of int is 4 bytes = 32 bits The range of int in binary notation is from to The first bit is sign bit. 0 means positive and 1 means negative. The range of int in decimal is from -2,147,483,648 to 2,147,483,647. Why there is one more number in negative than positive?

5 Binary -2,147,483,648 = = ,147,483,647 = So there is 0 to 2,147,483,647 are positive sign And -2,147,483,648 to -1 are negative sign So there is one more negative number than positive number exclude 0

6 Why do I get negative number? The first perfect square I got from my program is , and it computed from * 46341, and actual value for * = Why became ? = =

7 Equivalent array Let a and b be two integer arrays of the same length. We say that they are shift equivalent if array a can be right shifted to create array b. Write a function bool equivalent(int a[], int b[], int n) Which takes two arrays a and b of length n and returns true is they are shift equivalent and false otherwise.

8 Algorithm Step 1: For array size n, check right shift 0 place, 1 place,... n - 1 place. Step 2: For each i shift, use a loop to check whether the two array are i shift equivalent, if the elements at the equivalent position in array a and b are not the same, skip checking for the rest of the array, move on to the i + 1 shift. Step 3: Return true if all of the element in the array have been compared and all are shift i equivalent.

9 Assignment #3: Score the race

10 Score the race: Some number of teams are participating in a race. You are not told how many teams are participating but you do know that: Each team has a name, which is one of the uppercase letters A-Z. No two teams have the same name, so there are a maximum number of 26 teams. Each team has the same number of members. No two runners cross the finish line at the same time, so there is no tie. At the end of the race we can write the results as a string of characters indicating the order in which runners crossed the finish line. For example, ZZAZAA. We can see there are 2 teams: A and Z. Team A s runners finished in 3 rd, 5 th, and 6 th place. Team Z s runners finished in 1 st, 2 nd, and 4 th place.

11 Score the race: Each runner is assigned a score equal to their finishing place. In the example above, team Z s runners achieved scores of 1, 2 and 4. Team Z s runners scores were 3, 5, and 6 respectively. The team s score is the sum of the members score divided by the number of people in the team. So team A s score is (3+5+6)/3 = 4.66 and team Z s score is (1+2+4)/3=2.33 You need to write a program to score the race as described above.

12 Score the race Input: Your program will ask the user to enter a string of uppercase letters indicating the outcome of a race. Output: your program will output: The number of teams. The number of runners on the team. The names of the teams in alphabetical order together with the team score. The name and score of the winning team.

13 Score the race: So for example above the program will print: There are 2 teams. Each team has 3 runners. Team score A 4.66 Z 2.33 The winning team is team Z with a score of Your program should loop asking for input processing the data until the user enters done. Your program should detect the error condition where teams do not have the same number of runners. In that case, it should print an error message and resume by requesting the next input.

14 Basic Logic: 1. In the main function, there is a while loop so that it keeps asking the user to type the racing outcome until the user types done. 2. Check whether the outcome user types in is correct or not. 3. Get the number of teams and the number of members in each team. 4. Calculate the scores of each team and use these scores to compute the average for each team.

15 Score the race: The goal is to calculate the average rank for each team: ZZAZAA Race outcome(finishing order of the runners) The ranks of runners. If input[i] is A, it means that team A has a runner ranked (i+1). For each character in the outcome string, increment the total score of the correct team by the runner s rank.

16 Output: Enter the race outcome: ZZAZAA There are 2 teams. Each team has 3 runners. A: Z: The winning team is team Z with score Enter the race outcome: ABBCAC There are 3 teams. Each team has 2 runners. A: 3 B: 2.5 C: 5 The winning team is team B with score 2.5 Enter the race outcome: ABA The teams don't have the same number of runners. Enter the race outcome: done

17 goto - Using goto as loop: Label: //statements goto Label; - Using goto as branching(if): //statements if(true) goto Label; //more statements Label:

18 #include <iostream> using namespace std; int main() { int input; s1: cout<<"s1 step:please re input 1 or 0"<<endl; cin>>input; if (input==1) goto dead; else if(input==0) goto s2; s2: cout<<"s2 step:please re input 1 or 0"<<endl; cin>>input; if(input==1) goto s2; else if (input==0) goto s1; dead: cout<<" all of program is done."<<endl; return 0; }

19 Eight Queens The eight queens puzzle is the problem of placing eight chess queens on an 8x8 chessboard so that no two queens threaten each other. Thus, a solution requires that no two queens share the same row, column, or diagonal.