Description
Reading
ReadingfromC++HowtoProgram:
- Important: Chapter8.1,8.2,8.3,8.4
- 10
- 13
- 1,15.2(focusonlyonvector),15.3 IntroductiontoIterators
- 5(again,onlyvectors)
Assignment
- WhatistheoutputofthefollowingC++codefragment? Tracethecode’soperationtosupportyour answer: keeptrackofeachvariable’scurrentvalue,andindicatewhatactualvaluesthepointerspoint to.
#include <iostream> using namespace std;
double Blah(int *p) { *p = *p + 5; double local = *p / 2; return local;
}
int main() { int x = 10; int *y = &x; double z = Blah(y);
cout << x << endl << z;
}
- WriteaC++functionSolveQuadraticwhichsolvesaquadraticequationoftheformax2+bx+c=0 when given the coe cients a, b, and c. Your function should take three double parameters for the threecoe cients, plustwodoublepointer parametersthatyouwillusetosavethetwosolutionsto theequation. Youwillreturnanintegerindicatingthenumberofrealsolutionstotheequation.
Yourfunctionshouldnotdoanyinputoroutput;itshouldonlycalculateandsetthesolutionvariables, andreturnthenumbeofsolutions.
Exampleusage: double xSolution1, xSolution2;
double a, b, c;
// suppose a, b, and c are given values from the user int numberOfSolutions = SolveQuadratic(a, b, c, &xSolution1, &xSolution2); Testyourcodetomakesureitworksinthefollowingscenarios:
| a | b | c | numberOfSolutions | xSolution1 | xSolution2 | Explaination |
| 1 | 2 | 1 | 1 | -1 | 0 | For x2+2x+1=0,the
onlysolutionis x=−1 |
| 1 | 0 | 1 | 0 | 0 | 0 | Norealsolutionto x2+1=0 |
| 1 | -3 | -4 | 2 | 4 | -1 | For x2−3x−4=0,the solutionsare x=4and
x=−1 |
1
- Inthefollowingcodefragment:
string a = hello ; string b = a; string *c = &a; string &d = *c; string e = *c;
How many instances of the string type exist in memory? Draw a picture of automatic storage forthesevariables.
- Foreachfunctiondescription, decide if the function should accept its parameter as a string, a string*, a string&, or a const string&:
- In FuncA, Ada will read individual characters from the string to make a computation. She will notmutatethestring.
- In FuncB, Ada will mutate the string parameter, but doesn’t want the original string passed to thefunctiontomutate.
- InFuncC,Adawillmutatethestringparameter,andthestringcannotbe null/nullptr.
- In FuncD, Ada does not want to duplicate the string passed to the function, and is prepared to handleanullvalueaswell.
- GiventhefollowingC++program:
#include <vector> #include <iostream> using namespace std;
void FA(vector<int> &p1) { // see part (a) p1.pop_back(); p1.push_back(0);
}
void FB(vector<int> p2) { FA(p2);
}
int main() { int x = 0;
vector<int> v = {1, 2, 3, 4};
FB(v);
cout << v.size() << ” ” << v[3];
}
- By the time the comment is reached at run time, how many actual vector objects exist in automaticstorage? Identifythem.
- At what point in the program will the parameter p2 be destroyed and removed from memory? Bespeci c.
- Whatistheprintedoutputofthisprogram?
