C++ Programming Code Examples

/* Implement Booth's Multiplication Algorithm for Multiplication of 2 signed Numbers This is a C++ Program to multiply two signed numbers using booth's algorithm. Booth's multiplication algorithm is a multiplication algorithm that multiplies two signed binary numbers in two's complement notation. Booth used desk calculators that were faster at shifting than adding and created the algorithm to increase their speed. Booth's algorithm is of interest in the study of computer architecture. */ #include<iostream> #include<conio.h> using namespace std; void add(int a[], int x[], int qrn); void complement(int a[], int n) { int j; int x[8] = { NULL }; x[0] = 1; for (j = 0; j < n; j++) { a[j] = (a[j] + 1) % 2; } add(a, x, n); } void add(int ac[], int x[], int qrn) { int j, c = 0; for (j = 0; j < qrn; j++) { ac[j] = ac[j] + x[j] + c; if (ac[j] > 1) { ac[j] = ac[j] % 2; c = 1; } else c = 0; } } void ashr(int ac[], int qr[], int &qn, int qrn) { int temp, j; temp = ac[0]; qn = qr[0]; cout << "\t\tashr\t\t"; for (j = 0; j < qrn - 1; j++) { ac[j] = ac[j + 1]; qr[j] = qr[j + 1]; } qr[qrn - 1] = temp; } void display(int ac[], int qr[], int qrn) { int j; for (j = qrn - 1; j >= 0; j--) cout << ac[j]; cout << " "; for (j = qrn - 1; j >= 0; j--) cout << qr[j]; } int main(int argc, char **argv) { int mt[10], br[10], qr[10], sc, ac[10] = { 0 }; int brn, qrn, j, qn, temp; cout << "\n--Enter the multiplicand and multipier in signed 2's complement form if negative--"; cout << "\n Number of multiplicand bit="; cin >> brn; cout << "\nmultiplicand="; for (j = brn - 1; j >= 0; j--) cin >> br[j]; //multiplicand for (j = brn - 1; j >= 0; j--) mt[j] = br[j]; // copy multipier to temp array mt[] complement(mt, brn); cout << "\nNo. of multiplier bit="; cin >> qrn; sc = qrn; //sequence counter cout << "Multiplier="; for (j = qrn - 1; j >= 0; j--) cin >> qr[j]; //multiplier qn = 0; temp = 0; cout << "qn\tq[n+1]\t\tBR\t\tAC\tQR\t\tsc\n"; cout << "\t\t\tinitial\t\t"; display(ac, qr, qrn); cout << "\t\t" << sc << "\n"; while (sc != 0) { cout << qr[0] << "\t" << qn; if ((qn + qr[0]) == 1) { if (temp == 0) { add(ac, mt, qrn); cout << "\t\tsubtracting BR\t"; for (j = qrn - 1; j >= 0; j--) cout << ac[j]; temp = 1; } else if (temp == 1) { add(ac, br, qrn); cout << "\t\tadding BR\t"; for (j = qrn - 1; j >= 0; j--) cout << ac[j]; temp = 0; } cout << "\n\t"; ashr(ac, qr, qn, qrn); } else if (qn - qr[0] == 0) ashr(ac, qr, qn, qrn); display(ac, qr, qrn); cout << "\t"; sc--; cout << "\t" << sc << "\n"; } cout << "Result="; display(ac, qr, qrn); }

/* Perhaps you have warm memories of doing arithmetic drills in grade school. You can give that same pleasure to your computer. C++ uses operators to do arithmetic. It provides operators for five basic arithmetic calculations: addition, subtraction, multiplication, division, and taking the modulus. Each of these operators uses two values (called operands) to calculate a final answer. Together, the operator and its operands constitute an expression. */ #include <iostream> using namespace std; int main() { int a, b; a = 7; b = 2; // printing the sum of a and b cout << "a + b = " << (a + b) << endl; // printing the difference of a and b cout << "a - b = " << (a - b) << endl; // printing the product of a and b cout << "a * b = " << (a * b) << endl; // printing the division of a by b cout << "a / b = " << (a / b) << endl; // printing the modulo of a by b cout << "a % b = " << (a % b) << endl; return 0; }

/* simple code example by main() function in C++ */ #include <iostream> using namespace std; int main() { int day = 4; switch (day) { case 1: cout << "Monday"; break; case 2: cout << "Tuesday"; break; case 3: cout << "Wednesday"; break; case 4: cout << "Thursday"; break; case 5: cout << "Friday"; break; case 6: cout << "Saturday"; break; case 7: cout << "Sunday"; break; } return 0; }

/* Standard Input Stream (cin) in C++ language */ // cin with Member Functions #include <iostream> using namespace std; int main() { char name[20], address[20]; cout << "Name: "; // use cin with getline() cin.getline(name, 20); cout << "Address: "; cin.getline(address, 20); cout << endl << "You entered " << endl; cout << "Name = " << name << endl; cout << "Address = " << address; return 0; }

/* namespaces in C++ language */ // A C++ code to demonstrate that we can define // methods outside namespace. #include <iostream> using namespace std; // Creating a namespace namespace ns { void display(); class happy { public: void display(); }; } // Defining methods of namespace void ns::happy::display() { cout << "ns::happy::display()\n"; } void ns::display() { cout << "ns::display()\n"; } // Driver code int main() { ns::happy obj; ns::display(); obj.display(); return 0; }

/* While Loop Statement in C++ language */ // program to find the sum of positive numbers // if the user enters a negative number, the loop ends // the negative number entered is not added to the sum #include <iostream> using namespace std; int main() { int number; int sum = 0; // take input from the user cout << "Enter a number: "; cin >> number; while (number >= 0) { // add all positive numbers sum += number; // take input again if the number is positive cout << "Enter a number: "; cin >> number; } // display the sum cout << "\nThe sum is " << sum << endl; return 0; }

/* For Loop Statement in C++ Language */ // C++ program to find the sum of first n natural numbers // positive integers such as 1,2,3,...n are known as natural numbers #include <iostream> using namespace std; int main() { int num, sum; sum = 0; cout << "Enter a positive integer: "; cin >> num; for (int i = 1; i <= num; ++i) { sum += i; } cout << "Sum = " << sum << endl; return 0; }

/* using #include directive in C language */ #include <stdio.h> int main() { /* * C standard library printf function * defined in the stdio.h header file */ printf("I love you Clementine"); printf("I love you so much"); printf("HappyCodings"); return 0; }

/* If Else Statement in C++ Language */ #include <iostream> using namespace std; int main () { // local variable declaration: int a = 100; // check the boolean condition if( a < 20 ) { // if condition is true then print the following cout << "a is less than 20;" << endl; } else { // if condition is false then print the following cout << "a is not less than 20;" << endl; } cout << "value of a is : " << a << endl; return 0; }

/* write a C program which demonstrate use of if-else-if ladder statement */ /* Program to Print Day Names using Else If Ladder in C++*/ #include <iostream> using namespace std; int main() { int day; cout << "Enter Day Number: "; cin >> day; cout << "Day is "; if (day == 1) cout << "Sunday" << endl; else if (day == 2) cout << "Monday" << endl; else if (day == 3) cout << "Tuesday" << endl; else if (day == 4) cout << "Wednesday" << endl; else if (day == 5) cout << "Thursday" << endl; else if (day == 6) cout << "Friday" << endl; else cout << "Saturday" << endl; return 0; }

/* arrays in C++ Language */ #include <iostream> using namespace std; int main() { // initialize an array without specifying size double numbers[] = {7, 5, 6, 12, 35, 27}; double sum = 0; double count = 0; double average; cout << "The numbers are: "; // print array elements // use of range-based for loop for (const double &n : numbers) { cout << n << " "; // calculate the sum sum += n; // count the no. of array elements ++count; } // print the sum cout << "\nTheir Sum = " << sum << endl; // find the average average = sum / count; cout << "Their Average = " << average << endl; return 0; }