Saturday, May 22, 2010

How are loops used in C++ functions?

am interested in C++ and am trying to learn as much as i can but i don't know how write a function that uses a loop in C++ code.





Say for example i want to write a function that uses a loop to find the sum of the squares of all integers between 1 and n. How would the function look like in C++ code? (if possible include the function prototype, declaration and definition)

How are loops used in C++ functions?
You need to use a for loop.





The syntax is:





for ( %26lt;var%26gt; = %26lt;intial value%26gt;; %26lt;condition%26gt;; %26lt;increment / decrement expression)


{


do_some_function(%26lt;var%26gt;)


}





The commands contained within the curly brackets are executed until the condition is no longer true.





e.g to loop an integer variable from 1 to 10:





int i;


for (i=1;i%26lt;11;i++)


{


cout %26lt;%26lt; "Number: "%26lt;%26lt; i %26lt;%26lt; endl;


}





This will output :





Number: 1


Number: 2


Number: 3


Number: 4


......etc


Number: 10
Reply:you can use a for loop or an while loop. i have attached a sample code for the for loop








#include %26lt;cstdlib%26gt;


#include %26lt;iostream%26gt;





using namespace std;





int main(int argc, char *argv[])


{


int i,n;


int square, sum;





cout%26lt;%26lt;"enter the number"%26lt;%26lt;endl;


cin%26gt;%26gt;n;


for (i = 0; i %26lt;=n; i++)


{


square = i*i;


sum = sum +square;


}


cout%26lt;%26lt;"the answer is "%26lt;%26lt;sum%26lt;%26lt;endl;


system("pause");





}








you can replace for with while; for example use, while (i%26lt;=n)


but then u have to increment using i++ within the loop.





Happy Coding!


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