#include <iostream>
using namespace std;
#include <math.h>
int main()
{
int x, n;
float sum= 0;
cout<<"Enter the value for x:";
cin>>x;
cout<<"Enter the number of terms";
cin>>n;
for (int i=0; i<n; i++)
sum = sum + Pow(x,i);
cout<<"Sum="<< Sum<<endl;
cin.get();
return 0;
}

(a) #include <iostream>
using namespace std;
#include <math.h>
#factorial function.
long int fact(int n)
{
long int f= 1;
for (int i = 1;i<n; i++)
f* = i;
return f
}
// main function
int main()
{
int x, y = 1;
float sum = 0;
cout<<"Enter the value for x:";
cin>>x;
for (int i=1;i<-6; i++)
{
sum = sum + y*((pow(x, 1))/fact(i));
y*=-1;
}
cout<<"Sum=" <<Sum<<endl;
cin.get():
return();
}
(b) #include <iostream>
using namespace std;
#include <math.h>
int main()
{
int M, L;
float sum = 0;
cout<<"Enter the value for M:";
cin>>M;
cout<<"Enter the number of terms";
cin>> L;
for (int i=1;i<=m; i++)
sum Sum + Pow(m,i)/i;
cout<<"Sum="<< Sum<<endl;
cin.get():
return 0;
}

#include <iostream>
using namespace std;
int main()
{
int a1, b1 lem, ged-1, p;
cout << "\n Enter 1st no:";
cin>>a1;
cout << "\n Enter 2nd no:";
cin >> b1;
p=a1*b1;
for (int i = al; i<-p; i++)
if (i%al == 0) && (i%b1 == 0)
{
1cm=i;
break;
}
cin.get():
cout << "L.C.M. =" <<lcm<<endl;
gcd=p/LCM;
cout<<"G.C.D="<< ged;
cin.get():
return 0;
}

An entry control loop checks the condition at the time of entry and if condition or expression becomes true then control transfers into the body of the loop. for loop and while loop are the examples of Entry Controlled Loop.
A while loop is a control flow statement that allows the loop statements to be executed as long as the condition is true.
Type: Entry control loop
Syntax:
while ( Text expression)
{
Body of the loop;
}
Statement-x;
The control flow and flow chart of the while loop is shown below:

Control flow:
Step 1: Test-expression is evaluated to either True or False;
Step 2: If test-expression is true;
(a) The body of the loop is executed.
(b) Control is transferred to step 1.
Step 3: If test-expression is false, the control exits the while loop.
Example:
int a = 1;
while (a<-10)
{
cout< a+=2;
}
Output
1 3 5 7 9

Control statements are statements that alter the sequence of flow of instructions.
Types of control statements:
1. Selection statement
The selection statement means the statement (s) executed, depends upon a condition. If a condition is true, a true block (a set of statements) is executed otherwise a false block is executed. This statement is also called decision statement or selection statement because it helps in making decision about which set of statements are to be executed.

2. Iteration (or looping) statement
An iteration (or loop) is a sequence of one or more statements that are repeatedly executed until a condition is satisfied. These statements are also called as control flow statements. It is used to reduce the length of code to reduce the time to execute program and takes less memory space.