1 Repetition Structure Examples Example 1 #include <iomanip> float number, sum=0; // number to be read cin >> number; // read first number cout << fixed << setprecision(3); while ( number > 0 ) // loop while number read > 0 sum = sum + number; cout << sum<<endl; // sum the positive number cin >> number; // read next number Example 3 cout << "Enter a number : "; int ival; for (int i=1;i<=5;i=i+1) cout << i << "x" << ival << "=" << i*ival << endl; return(0); Example 2 char letter; int counter=-1; // loop until 'q' is read ++counter; // increment letter counter cout <<" Enter a letter, q to end"<< endl; cin >> letter; // read next letter while ( letter!= 'q'); cout<<"the number of letters read is "<<counter<<endl; Example 4 // Outputs a table of x and sin(x) // Uses manipulators for output #include <cmath> #include <iomanip> float x, i; cout << fixed << showpoint; for (i = 0.0; i <= 1.0; i=i+0.1 ) x = 0.1 * i; cout << setprecision(1) << setw(4) << x; cout << setprecision(6) << setw(10) << sin(x) << endl;
2 Example 5 int counter, sum=0; for (counter = 1;counter < 10;++counter) sum = sum + counter; cout << "The sum is " <<sum<< endl;//display the sum cout << "Enter an integer greater"<< " than or equal to 0 and " << "less than 100: "; cin >> guess; cout << endl; if (guess == num) cout<<"you guessed the correct "<< "number."<< endl; isguessed = true; if (guess < num) cout << "Your guess is lower than the " << "number.\n Guess again!" << endl; cout << "Your guess is higher than "<< "the number.\n Guess again!"<< endl; i++; //end while cout << "The number guessed " << num; Example 6 //Flag-controlled while loop. //Number guessing game. #include <iostream > #include <ctime > //declare the variables int num; //variable to store the ranm number int guess,i=0; //variable to store the number //guessed by the user bool isguessed; //boolean variable to control the loop num = (rand() + time(0)) % 100; isguessed = false; while ((isguessed==false) && (i<10)) Example 7 // Program: Telephone Digits;Example of a sentinel- // controlled loop. This program converts uppercase // letters to their corresponding telephone digits. char letter; cout << "Program to convert uppercase "<<"letters to their corresponding telephone digits." << endl;
3 cout << "To stop the program enter #." << endl; cout << "Enter a letter: "; cin >> letter; cout << endl; while (letter!= '#') cout <<"The letter you entered is: "<<letter<< endl; cout << "The corresponding telephone "<<"digit is: "; if (letter >= 'A' && letter <= 'Z') switch (letter) case 'A': case 'B': case 'C': cout << "2" <<endl; case 'D': case 'E': case 'F': cout << "3" << endl; case 'G': case 'H': case 'I': cout << "4" << endl; case 'J': case 'K': case 'L': cout << "5" << endl; case 'M': case 'N': case 'O': cout << "6" << endl; case 'P': case 'Q': case 'R': case 'S': cout << "7" << endl; case 'T': case 'U': case 'V': cout << "8" << endl; case 'W': case 'X': case 'Y': case 'Z': cout << "9" << endl; cout << "Invalid input." << endl; cout << "\nenter another uppercase " << "letter to find its corresponding telephone digit."<< endl; cout << "To stop the program enter #."<< endl; cout << "Enter a letter: "; cin >> letter; cout << endl; //end while Example 8 int sum, i=0; // the sum of the numbers read bool ne; // used to control the while loop int number; // the number read sum = 0; // initialize the sum ne = false; // initialize the boolean variable ne cout << "Enter numbers, negative number to end "; cin >> number; // read next number if ( number > 0 ) // sum number if
4 i++; sum = sum + number; //sum the positive numbers ne = true; // terminate the loop while (!ne ) ;// loop while not ne cout << "Sum = " << sum<<endl; cout << "i = " << i; Example 9 /* Program to reverse the digits of a number */ #include<iostream> int number, rev_number=0, right_digit; cout << "Enter your number: "; cin >> number; right_digit = number % 10; rev_number=rev_number*10+right_digit; number = number / 10; while ( number!= 0 ); cout <<"After reversing digits : "<<rev_number <<endl; system("pause"); Another version /* Program to reverse the digits of a number */ #include<iostream> int number, rev_number, rev_number1, right_digit; cout << "Enter your number: "; cin >> number; rev_number1=number % 10; number = number / 10; right_digit = number % 10; rev_number=rev_number*10+right_digit; number = number / 10; while ( number!= 0 ); cout <<rev_number*10 + rev_number1 <<"\n"; Example 10 int q,w; char z; cout<<"please enter the first number :" ; cin>>q; cout<<"please enter the second number :" ; cin>>w; cout<<"answer is = " ; cout<<q+w<<endl; cout<<"do you want to add more numbers:" ; cin>>z;
5 while(z=='y' z=='y'); Example 11 // average.cpp - average a sequence of numbers int num=0, sum=0; cout << "Enter number (-1 to stop) : "; int ival; while (ival!= -1) sum = sum + ival; num = num + 1; cout << "Enter number (-1 to stop) : "; if (num==0) cout << "No numbers entered" << endl; cout << "Average=" << (uble)sum/num << endl; return(0); Example 12 float r; int ival, p=1,i=0; cout << "Enter a number (99 to end) : "; while (ival!= 99) i++; p = p * ival; cout << "Enter a number (99 to end) : "; r=p/i; cout << "Result=" << r << endl; return(0); Example 13 int i, j; for(i=1;i<=5;i++) for(j=1;j<=10-2*i;j++) cout<<" "; for(j=1;j<=4*(i-1)+1;j++)cout<<"*"; for(i=5;i>=1;i--) for(j=1;j<=10-2*i;j++) cout<<" "; for(j=1;j<=4*(i-1)+1;j++)cout<<"*";
6 Example 14 int i, j, n, b=1; cout<<"please enter a width "; cin >> n; cout << endl; int p = n/2; if (n%2==0 && p%2==1) b=0; while (b==1); for(i=1;i<=n/2;i++) for(j=1;j<=n-2*i;j++) cout<<" "; for(j=1;j<=4*(i-1)+1;j++)cout<<"*"; for(i=n/2;i>=1;i--) for(j=1;j<=n-2*i;j++) cout<<" "; for(j=1;j<=4*(i-1)+1;j++)cout<<"*"; Example 15 using namespace std ; int main () uble p=1;// p is a great number so use uble int a=3; while( a<=15)// after while not put ";" p=p*a; a++; cout << " p = " << p<< " a = " << a<<endl; cout << "Result = "<< p; OR #include <cstdlib> int i; uble p=1; for(i=3;i<=15;i++) p*=i; cout<<"result = : "<<p; Example 16
7 char Typedletters; int nump=0; cout << "Start typing a character: "; cin >> Typedletters; while (Typedletters!= '$' ) nump++; cout << "Start typing a character: "; cin >> Typedletters; cout << "number of small character " << nump << endl; Example 18 int i, j; for(i=0;i<7;i++) for(j=7-i;j>=1;--j)cout<<"*"; Example 17 int i, j, k; for(i=1;i<=7;i++) for(j=1;j<=i;++j) cout<<j; for(k=7-i;k>=1;k--) cout<<"*"; Example 19 int m1,m2,m3,i=0; cout <<"Please enter three marks : "; cin>> m1>>m2>>m3; if (m1<40) i++; if (m2<40) i++; if (m3<40) i++; // mark is absent if we type 101 if (m1!= 101 && m2!=101 && m3!=101) if (i<=1) if (((m1+m2+m3)/3.0) >=50) cout << "You Pass!" << endl;
8 cout << "You Fail!" << endl; cout << "You Fail!" << endl; cout << "You Fail!" << endl; // ending brace aligned with the start of the statement Example 20 char choice,tchoice,bchoice; int Mchoice; cout << "T : Toyota "<<endl; cout << "M : Mercedes "<<endl; cout << "B : BMW "<<endl; cout << "E : Exit "<<endl; cout << " Choice : "; cin>>choice; if (choice == 'T') cout << "C : Camry "<<endl; cout << "O : Orion "<<endl; cout << "E : Exit "<<endl; cout << " Choice : "; cin>>tchoice; while(tchoice!='e'); if (choice =='M') cout << "1 : E300 "<<endl; cout << "2 : S500 "<<endl; cout << "3 : Exit "<<endl; cout << " Choice : "; cin>>mchoice; while(mchoice!=3); if (choice =='B') cout << "M : M5 "<<endl; cout << "N : N6 "<<endl; cout << "E : Exit "<<endl; cout << " Choice : "; cin>>bchoice; while(bchoice!='e'); while ( choice!='e') ;// loop while not ne