2/17/2016IT 2791 Homogeneous aggregate // Using array string name[20]; int mid1[20]; int final[20]; double GPA[20]; name[0] = "Tom"; GPA[2] = 3.21; name: Tom, John, student-3, student_4, , student-20 mid1: 70, 67, 86, 59, , 80 final: 69, 77, 79, 64, , 90 GPA: 3.02, 2.89, 3.21, 2.78, , 3.67 // Using tvector class #include "tvector.h" tvector name(20); tvector mid1(20); tvector final(20); tvector GPA(20); name[1] = "John"; GPA[19] = 3.67; in STL (Standard Template Library)

2/17/2016IT 2792 Search in a tvector (or an array) // Using tvector class #include "tvector.h" tvector name(20); tvector mid1(20); tvector final(20); tvector GPA(20);..... // What is Susan's GAP? for (int i=0; i < name.length(); i++) { if (name[i] == "Susan") cout << GPA[i]; } Sequentially

2/17/2016IT 2793 What can be in an Array // Using tvector class..... struct student { string name; int mid1; int final; double GPA; }; struct student class279[20];..... // What is Susan's GAP? for (int i=0; i < class279.length(); i++) { if ( (class279[i]).name == "Susan") cout << (class279[i]).GPA; } A bit old fashioned

2/17/2016IT 2794 The index can be an Enumerated Type enum day {Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday}; tvector MyclassHr(7); MyclassHr[Monday] = 2; MyclassHr[Tuesday] = MyclassHr[Thursday] = 0; MyclassHr[Wednesday] = 4; enum day ThreeDays[3]; enum day ADay; ThreeDay[0]=Saturday; if (ADay == Saturday || ADay == Sunday) cout << "It's weekend"; day FirstDay = day(0); Sunday Monday Tuesday Wednesday Thursday Friday Saturday Monday Tuesday Wednesday Thursday Friday Saturday Sunday

2/17/2016IT 2795 Two dimensional array, Matrix // Using array int A[3][3]; int B[3][3]; int C[3][3]; A[1][2] = 3; A[1][1] = 1; C[2][1] = A[2][1]+B[2][1]; // Using apmatrix class #include "apmatrix.h" apmatrix A(3,3); apmatrix B(3,3); apmatrix C(3,3); A[1][2] = 3; A[1][1] = 1; C[2][1] = A[2][1]+B[2][1]; =

2/17/2016IT 2796 in STL (Standard Template Library) #include struct student { string name; int ssn; }; student s; vector IT279; while (true) { cout << "Input SSN:"; cin >> s.ssn; if (s.ssn == 0) break; cout << "Input name:"; cin >> s.name; IT279.push_back(s); } for (int i=0;i< IT279.size();i++) { cout << "\nName:" << IT279[i].name << " "; cout << "SSN:" << IT279[i].ssn; } student 1 student 2 student 3 student 4 IT279 IT279[3] IT279[2] IT279[1] IT279[0]

2/17/2016IT 2797 Resize a vector student 1 student 2 student 3 student 4 CS CS[3] CS[2] CS[1] CS[0] CS[4] CS[5] the last push back here CS.resize(6)

2/17/2016IT 2798 Reserve a vector student 1 student 2 student 3 student 4 CS CS[3] CS[2] CS[1] CS[0] CS[4] CS[5] the last push back here CS.resize(6) CS.reserve(8)

2/17/2016IT 2799 pop back a vector student 1 student 2 student 3 student 4 CS2 CS2[3] CS2[2] CS2[1] CS2[0] CS2[4] CS2[5].... CS2.resize(6); CS2.pop_back(); reserved size

2/17/2016IT Stack and Queue Stack: LCFS (Last Come First Service) c1c2 c3 c5 c4 c2c3c4 c5 c1 Queue: FCFS (First Come First Service) Front Back

2/17/2016IT in STL (Double Ended Queue) #include deque CS2; while (true) { cout << "Input SSN:"; cin >> s.ssn; if (s.ssn == 0) break; cout << "Input name:"; cin >> s.name; CS2.push_front(s); CS2.push_back(s); } for (int i=0;i<CS2.size();i++) { cout << "\nName:" << CS2[i].name << " "; cout << "SSN:" << CS2[i].ssn; } student 2 student 1 student 2 CS2 CS2[3] CS2[2] CS2[1] CS2[0]

2/17/2016IT pop back and pop front a deque student 1 student 2 student 3 student 4 student 5 CS2 CS2[3] CS2[2] CS2[1] CS2[0] CS2[4].... CS2.pop_front(); CS2.pop_back(); student 1 student 2 student 3 student 4 student 5 CS2 CS2[2] CS2[1] CS2[0] CS2[4]

2/17/2016IT A Pointer: an address, a reference, a location of the computer memory A pointer of what? int, char, bool, double, or any kind of data type need to know so the computer knows how to read or store the contents of the memory. Can be

2/17/2016IT // define pointers int a, *ap; // can’t use a and *a at the same time; double b, *bp; token k, *kp; a is an integer, ap is a pointer to an integer; b is a double, bp is a pointer to a double; k is a token, kp s a pointer to a token. Define pointers

2/17/2016IT A Pointer points to a location of the computer memory int a=5; int *ap; double b=2.3; double *bp; token k; token *kp; bp = new double; *bp = 3.14; *ap = 7; // not new-ed yet a ap b bp k kp 4 bytes } ? ? FFFFA080 FFFFA

2/17/2016IT A Pointer points to a location of the computer memory double a=5.1; double *ap; double *b,*c; ap = &a; // &a :the address of a *ap=1.7; b = new double; *b = 3.14; b = &a; c = b; a ap b c 4 bytes } new FFFFA080 FFFFA

2/17/2016IT The name of an array is a pointer int a[4]={5,60,700,8000}; int *p; p=a; cout << *p << endl; cout << *p+1 << endl; cout << *(p+1) << endl; cout << *(p+2) << endl; cout << *(p+3) << endl; cout << *(p+4) << endl; apap 4 bytes } FFFFA080 FFFFA

2/17/2016IT Dynamic arrays, resizable arrays p = new int[3]; for (int i=0; i<3; i++) p[i] = i; 4 apaapa p = new int[a]; for (int i=0; i<4; i++) p[i] = i*i; int a[3]={5,60,700}; int *p,a=4;

2/17/2016IT Create and Delete Dynamic arrays int a[3]={5,60,700}; int *p,a=4; p = new int[3]; for (int i=0; i<3; i++) p[i] = i; delete [] p; p = new int[4]; for (int i=0; i<4; i++) p[i] = i*i; a p a

2/17/2016IT Forget to Delete Dynamic arrays int a[3]={5,60,700}; int *p,i; p = new int[3]; for (i=0; i<3; i++) p[i] = i; // delete [] p; p = new int[4]; for (i=0; i<4; i++) p[i] = i*i; a p i

2/17/2016IT An array  pointers int a[4]={0,1,4,9} int *p; p = new int[3]; for (i=0; i<=3; i++) { p[i] = i; *(p+i) *= 2; } // a[4] = 16; *a = a[0]*a[0]; *(a+1) = a[1]*a[1]; *(a+2) = a[2]*a[2]; *(a+3) = a[3]*a[3]; //*(a+4) = a[4]*a[4]; apap X X

2/17/2016IT Arrays  Pointers int *a[4]; int **p; a[1] = new int[2]; a[2] = new int[3]; a[3] = new int[3]; p = new int*[3]; p[2] = new int[2]; p[2][0]=5; p[2][1]=7; apap 22 a[0] a[1] a[2] a[3] p[0] p[1] p[2]

2/17/2016IT Call by value double fun(int n, double p) { for (int i=0; i < 2; i++) p = p-n; return p; } npinpi int main() { int i=1,k=4; double p, s=123.4; p = fun(i+k,s); cout << i << “\n“ << k << “\n“ << p << “\n“ << s; } ikpsikps 1+4=

2/17/2016IT Call by reference double fun(int n, double & p) { for (int i=0;i < 2;i++) p = p-n; return p; } npinpi int main() { int i=1,k=4; double p, s=123.4; p = fun(i+k,s); cout << i << “\n“ << k << “\n“ << p << “\n“ << s; } ikpsikps &s 1+4=

2/17/2016IT Call by Value vs. Call by Reference int add_one_V(int n) { n++; cout << “1:“ << n << endl; return n; } 5 n int main() { int a,b=5; a = add_one_V(b); cout << “2:“ << a << “ “ << b << endl; a = sub_one_R(b); cout << “3:“ << a << “ “ << b << endl; } 1:6 2:6 5 3:4 4 abab int sub_one_R(int & n) { n--; return n; } n &b

2/17/2016IT Passing Arrays as Parameters int top(int a[]) { int i=0; return a[i]; } 0 aiai int main() { int a[4]={10,200,300,400}; cout << top(a) << endl; cout << third(a) << endl; } a int third(int a[]) { int i=2; return a[i]; } 2 aiai a+2

2/17/2016IT Arrays passed as References void fun(int a[]) { int i=2; a[i] += 5; } 2 aiai int main() { int a[4]={10,200,300,400}; fun(a); cout << a[0] << “ “; cout << a[1] << “ “; cout << a[2] << “ “; cout << a[3] << endl; return 1; } a a[2]

2/17/2016IT Passing the size of an Array int main() { const int size=4; int a[size]={1,2,3,4}; add_one_to_all(a,size); for (int i=0;i<size;i++) cout << a[i] << “ “; return 1; } 4 0 size i a 1 2 void add_one_to_all(int A[], int size) { for (int i=0;i<size;i++) A[i]++; } 0 4 i A size

2/17/2016IT Vector passed as Value ? (right? wrong?) int main() { vector a(4); int i; for (i=0;i<a.size();i++) a[i]=i+1; add_one_to_all(a); for (i=0;i<a.size();i++) cout << a[i] << “ “; } iaia void add_one_to_all(vector v) { for (int i=0;i<v.size();i++) v[i]++; } iviv

2/17/2016IT Vector passed as Reference int main() { vector a(4); for (int i=0;i<a.size();i++) a[i]=i+1; add_one_to_all(a); for (int i=0;i<a.size();i++) cout << a[i] << “ “; } iaia 1 2 void add_one_to_all(vector & v) { for (int i=0;i<a.size();i++) a[i]++; } 0 iviv &a

2/17/2016IT C-string is an array of char char *a = "Dennis"; char b[7] = {'D','e','n', 'n','i','s','\0'}; char *c=b; cout << *a << “ “ << b[0] << endl; cout << *(a+2) << “ “ << b[2] << endl; cout << a << “ “ << b << endl; char *d[2] = {c, "Li"}; cout << d[0] << " " << d[1] << endl;; abcdabcd 4 bytes } D n Dennis Dennis Li } 1 byte ‘D’ ‘e’ ‘n’ ‘i’ ‘s’ 0 ‘L’ ‘i’ d[0] d[1] ‘D’ ‘e’ ‘n’ ‘i’ ‘s’ 0