Loops
Loops are used to repeat a block of code. Being able to have your program repeatedly execute a block of code is one of the most basic but useful tasks in programming — many programs or websites that produce extremely complex output (such as a message board) are really only executing a single task many times.
FOR – for loops are the most useful type. The syntax for a for loop is:
For (variable initialization; condition; variable update) { Code to execute while the condition is true }
The variable initialization allows you to either declare a variable and give it a value or give a value to an already existing variable. Second, the condition tells the program that while the conditional expression is true the loop should continue to repeat itself.
WHILE – WHILE loops are very simple. The basic structure is
while (condition) {Code to execute while the condition is true} the true represents a Boolean expression. It can be any combination of Boolean statements that are legal.) Notice that a while loop is the same as a for loop without the initialization and update sections. However, an empty condition is not legal for a while loop as it is with a for loop.
Example:
#include <iostream> Using namespace std; // So we can see cout and endl int main() { int x = 0; // Don't forget to declare variables while ( x < 10 ) { // While x is less than 10 cout<< x <<endl; x++; // Update x so the condition can be met eventually } cin.get(); }
Here is an example of a program which has loops (factorial calculator):
/* Source code to find factorial of a number. */ #include <iostream> using namespace std; int main() { int x , factorial=1; cout << "Please enter a non-negative number: " << endl; cin >> x; for(int a=1; a<=x; a++)//HERE IS THE "FOR" LOOP { factorial=factorial*a; } cout << "The factorial of your number is " << factorial << endl; cout << "Would you like to play again? "; string answer; cin >> answer; do { int x , factorial=1; cout << "Please enter a non-negative number: " << endl; cin >> x; for(int a=1;a<=x;a++)//HERE IS THE "FOR" LOOP { factorial=factorial*a; } cout << "The factorial of your number is " << factorial << endl; cout << "Would you like to play again ? "; cin >> answer; }while (answer =="yes");//HERE IS THE "WHILE" LOOP if (answer== "no") { cout << "AS YOU WISH MASTER, MAY THE FORCE BE WITH YOU! " << endl; } return 0; }
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-The Admin.
Using Loops FOR and WHILE by esaupreciado is licensed under a Creative Commons Attribution 4.0 International License.