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Spec of the program outputs:

Spec of the program outputs:. What's your name? Dennis Hi! Dennis! Input the price for 10% discount: 200 Input the quantity: 5 Input the price for 20% discount: 500 Input the quantity: 4 Total items: 9 Amount: 2500.00

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Spec of the program outputs:

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  1. Spec of the program outputs: What's your name? Dennis Hi! Dennis! Input the price for 10% discount: 200 Input the quantity: 5 Input the price for 20% discount: 500 Input the quantity: 4 Total items: 9 Amount: 2500.00 Tax rate: 8.5% Total amount: 2712.50 Press any key to continue Chung-Chih Li @ ISU ITK 279

  2. CPP program for the baby counter (part 1) #include <iostream> #include <string> using namespace std; void main() { string name; int itemNo = 0; int a,b; int total_item; float price_1, price_2; const float taxRate = 0.085; float discount = 0.1, Discount (0.2); double amount; cout << "What's your name? "; cin >> name; cout << "\nHi! " << name << "!\n\n"; cout.setf(ios::fixed); cout.setf(ios::showpoint); cout.precision(2); Chung-Chih Li @ ISU ITK 279

  3. CPP program for the baby counter (part 2) cout << "\t Input the price for "; cout << (int) (discount*100) << "% discount: "; cin >> price_1; cout << "\t Input the quantity: "; cin >> a; cout << "\t Input the price for "; cout << (int) (Discount*100) << "% discount: "; cin >> price_2; cout << "\t Input the quantity: "; cin >> b; total_item = a + b; cout << "\n\n\t Total items:\t" << total_item << endl; amount = price_1*a*(1-discount)+price_2*b*(1-Discount); cout << "\t Amount:\t" << amount << endl; cout << "\t Tax rate: \t" << taxRate << endl; amount = (price_1*a*(1-discount)+price_2*b*(1-Discount)) *(1+taxRate); cout << "\t Total amount: \t" << amount << endl << endl; } Chung-Chih Li @ ISU ITK 279

  4. Directives These two statements use the include directive to ask the compiler to provide necessary accesses to the twostandard libraries. #include <iostream> #include <string> using namespace std; /* This is a program that can do something .. By Chung-Chih Li */ void main() { string name; // string is a class int itemNo = 0; int a,b; int total_item; float price_1, price_2; const float taxRate = 0.085; float discount = 0.1, Discount = 0.2; double amount; cout << "What's your name? "; cin >> name; cout << "\nHi! " << name << "!\n\n"; The directive using asks the compiler to use the definitions in namespace std. alternatively: (for this program) using std::cin; using std::cout; using std::endl; using std::ios; using std::string; Chung-Chih Li @ ISU ITK 279

  5. Comments #include <iostream> #include <string> using namespace std; /*This is a program that can do something .. By Chung-Chih Li */ void main() { string name; //string is a class int itemNo = 0; int a,b; int total_item; float price_1, price_2; const float taxRate = 0.085; float discount = 0.1, Discount = 0.2; double amount; cout << "What's your name? "; cin >> name; cout << "\nHi! " << name << "!\n\n"; Chung-Chih Li @ ISU ITK 279

  6. Identifiers #include <iostream> #include <string> using namespace std; void main() { string name; int itemNo = 0; int a,b; int total_item; float price_1, price_2; const float taxRate = 0.085; float discount = 0.1, Discount (0.2); double amount; cout << "What's your name? "; cin >> name; cout << "\nHi! " << name << "!\n\n"; Chung-Chih Li @ ISU ITK 279

  7. Variables and Types #include <iostream> #include <string> using namespace std; void main() { stringname; intitemNo = 0; inta,b; inttotal_item; floatprice_1, price_2; constfloattaxRate = 0.085; floatdiscount = 0.1, Discount (0.2); doubleamount; cout << "What's your name? "; cin >> name; cout << "\nHi! " << name << "!\n\n"; Chung-Chih Li @ ISU ITK 279

  8. Literals (constants) string name; int itemNo = 0; int a,b; int total_item; float price_1, price_2; const float taxRate = 0.085; float discount = 0.1, Discount (0.2); double amount; cout << "What's your name? "; cin >> name; cout << "\nHi! " << name << "!\n\n"; cout << "\t Input the price for "; cout << (int) (discount*100) << "% discount: "; cin >> price_1; cout << "\t Input the quantity: "; cin >> a; Chung-Chih Li @ ISU ITK 279

  9. Value Initialization #include <iostream> #include <string> using namespace std; void main() { string name; int itemNo = 0; int a,b; int total_item; float price_1, price_2; const float taxRate = 0.085; float discount = 0.1, Discount (0.2); double amount; cout << "What's your name? "; cin >> name; cout << "\nHi! " << name << "!\n\n"; Chung-Chih Li @ ISU ITK 279

  10. Simple Types sizeof(short) : 2 sizeof(s) : 2 sizeof(int) : 4 sizeof(i) : 4 sizeof(long) : 4 sizeof(l) : 4 sizeof(double) : 8 sizeof(d) : 8 sizeof(long double) : 8 sizeof(u) : 8 sizeof(char) : 1 sizeof(c) : 1 sizeof(bool) : 1 sizeof(b) : 1 Press any key to continue short s; int i; long l; float f; double d; longdouble u; char c; bool b; cout << "sizeof(short) :\t\t " << sizeof(short) << " sizeof(s) : " << sizeof(s) << endl; Chung-Chih Li @ ISU ITK 279

  11. Assignment I total_item = a + b; total_item = a; a = a; amount = (price_1*a*(1-discount)+price_2*b*(1-Discount)) *(1+taxRate); L-value = R-value a + 1 = a Chung-Chih Li @ ISU ITK 279

  12. Assignment II a = 3; a *= a*= 2; cout << a; a += 2; a /= 2; a %= 2; a *= a; ........ total_item = a + b; cout << (a = 2*3); a = b = 3; a = (b = 3); ? a = 3; a = a * ( a *=2); cout << a; ? a = 3; a = a * ( a = a*2); cout << a; ? a = a+b = 3; 36 (a = b) = 3; Chung-Chih Li @ ISU ITK 279

  13. Arithmetic operators and their precedence rules + - * / % amount = (price_1*a*(1-discount)+price_2*b*(1-Discount))* (1+taxRate); precedence rules: + - % * / > a-b-c-d ((a-b)-c)-d left-to-right a=b=c=d a=(b=(c=d)) Chung-Chih Li @ ISU ITK 279

  14. Increment and Decrement i = i+1; i = i-1; i++; ++i; i--; --i; n = i; i = i+1; n = (i++); n = (++i); i = i+1; n = i; i=0; i = i+1; i = i+1; s = i; i = i+1; cout... i=0; s = (++(++i))++; cout << i << endl; cout << s << endl; Chung-Chih Li @ ISU ITK 279

  15. Type Coercion (Type Casting) float discount = 0.1, Discount (0.2); cout << "\t Input the price for "; cout << (int) (discount*100) << "% discount: "; ...... cout << "\t Input the price for "; cout << (int) (Discount*100) << "% discount: "; Input the price for 10% discount: 200 Input the quantity: 5 Input the price for 20% discount: 500 Input the quantity: 4 Chung-Chih Li @ ISU ITK 279

  16. Type Coercion (Type Casting), (Implicit) double score_1=1, score_2=2; int no_test=2; double average; ..... average = (score_1 + score_2 )/ no_test; int i=1, j=2, k=3; double r=1, s=2, t=3; double a,b,c,d,e; ... a = r/t + s/t; // 0.33333... + 0.66666... b = i/k + j/k; // 1/3 + 2/3  0 + 0 c = (i+j)/k; // (1+2) / 3  3/3 d = i/t + j/k; // 0.33333... + 0 e = (i+r)/k; // (1+1.0)/3  2.0/3  0.66666 Chung-Chih Li @ ISU ITK 279

  17. Type Casting, (Explicit) int score_1=1, score_2=2; int no_test=2; double average; ..... average = (score_1 + score_2 )/ no_test; older form 1 average = (score_1 + score_2 )/ ((double)no_test); 1.5 average = (double)(score_1 + score_2 )/no_test; 1 average = (double)((score_1 + score_2 )/no_test); 1.5 average =(score_1 + score_2 + 0.0)/no_test; ...... (.....)/ double(no_test); ...... (.....)/ static_cast<double>(no_test); new notation for C++ standard Chung-Chih Li @ ISU ITK 279

  18. More on Type Casting int i; i = 1/2.0; double a; a = 1/2.0; a = 0.5 a = static_cast<int>(1/2.0); a = 0.0 double p=2.99; const double tax=0.085; double total = p*(1+tax); cout << total; 3.24415 total = double(int(p*(1+tax)*100))/100; 3.24 total = (int(p*(1+tax)*100))/100; 3 Chung-Chih Li @ ISU ITK 279

  19. cout, the Class #include <iostream> #include <string> using namespace std; ref: page 490 cout.setf(ios::fixed); cout.setf(ios::showpoint); cout.precision(2); fixed point: 1229312345.67 12.00 scientific notation: 1.2293e+009 Chung-Chih Li @ ISU ITK 279

  20. The insertion operator:<< Standard Console I/O: cin and cout cout << x; Insert the value of x to the standard output stream. cout << x,y; cout << x << y; x=5; y=9; cout << x << y << “ “ << x << “ “ << y << “d“; 59 5 9d The printing will take place at the end of the cout statement. After printing, the output stream will become empty again. Why we need a output stream? 59 5 9d Some location in the main memory (e.g. 004787f4) Chung-Chih Li @ ISU ITK 279

  21. Evaluation order in a << statement i=0; cout << i++ << i++ << i++ << endl; 210 2 3 1 2 0 1 0 i cout << (cout << "a") << "B" << endl; a B 004787f4B 004787f4 a a004787f4B cout << "a" << (cout << "B") << endl; Ba004787f4 Chung-Chih Li @ ISU ITK 279

  22. The extraction operator:>> cin >> x: Extract the value in the input stream to variable x. cin >> x,y; cin >> x >> y; cin >> x >> y; cin >> name; 5 9.6 Dennis • Values in the input stream are separated by blank space or returns, or some proper delimiters. • If there are more variables than values in the stream, the computer will halt and wait for more inputs. Chung-Chih Li @ ISU ITK 279

  23. The extraction operator:>> int i,j,k; cout << "Input 3 numbers, 1st:"; cin >> i; cout << “2nd:"; cin >> j; cout << “3rd:"; cin >> k; cout << "The three numbers are:" << i << " " << j << " " << k << "\n"; Input 3 numbers, 1st:10 2nd:200 3rd:3000 The three numbers are:10 200 3000 Input 3 numbers, 1st:1 2 3 2nd:3rd:The three numbers are:1 2 3 Input 3 numbers, 1st:2 2nd:4.3 3rd:The three numbers are:2 4 -858993460 Chung-Chih Li @ ISU ITK 279

  24. Escape Sequences In a string that to be printed, C++ considers a character that immediately follows \ as a special symbol that “escapes” from its regular C++ meaning.. \n \t \\ \” \’ cout << "What's your name? "; cin >> name; cout << "\nHi! \"" << name << "\"!\n\n"; cout << "\t Input the price for "; What's your name? Dennis Hi! "Dennis"! Input the price for 10% discount: Chung-Chih Li @ ISU ITK 279

  25. More on Escape Sequences cout << x,y; cout << x y; exception: cout << "Dennis ""Li ""!"; cout << "What's your name? "; cin >> name; cout << "\nHi! ""<< name << ""!\n\n"; cout << "\t Input the price for "; What's your name? Dennis Hi! << name << ! Input the price for 10% discount: Chung-Chih Li @ ISU ITK 279

  26. Nasty C++ Programs OK! a = (++n) + (i++); n = 0; a = n + (++n); n = 0; a = (++n) + n; n = 0; a = (++n) + (++n); a=0+1 a=1+1 a=1+1 a=1+0 2 2 ? 4 KISS principle: Keep It Simple, Stupid!! Chung-Chih Li @ ISU ITK 279

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