# C Exercises: Calculate the sum of the series [ 1-X^2/2!+X^4/4!- .........]

## C For Loop: Exercise-18 with Solution

Write a program in C to find the sum of the series [ 1-X^2/2!+X^4/4!- .........].

**Sample Solution:**

**C Code:**

```
#include <stdio.h>
void main()
{
float x,sum,t,d;
int i,n;
printf("Input the Value of x :");
scanf("%f",&x);
printf("Input the number of terms : ");
scanf("%d",&n);
sum =1; t = 1;
for (i=1;i<n;i++)
{
d = (2*i)*(2*i-1);
t = -t*x*x/d;
sum =sum+ t;
}
printf("\nthe sum = %f\nNumber of terms = %d\nvalue of x = %f\n",sum,n,x);
}
```

**Flowchart: **

or

```
#include <stdio.h>
void main()
{
float x,s,t,num=1.00,fac=1.00;
int i,n,pr,y=2,m=1;
printf("Input the Value of x :");
scanf("%f",&x);
printf("Input the number of terms : ");
scanf("%d",&n);
s=1.00; t=1.00;
for (i=1;i<n;i++)
{
for(pr=1;pr<=y;pr++)
{
fac=fac*pr;
num=num*x;
}
m=m*(-1);
num=num*m;
t=num/fac;
s=s+t;
y=y+2;
num=1.00;
fac=1.00;
}
printf("\nthe sum = %f\nNumber of terms = %d\nvalue of x = %f\n",s,n,x);
}
```

Sample Output:

Input the Value of x :2 Input the number of terms : 5 the sum = -0.415873 Number of terms = 5 value of x = 2.000000

**Flowchart: **

**C Programming Code Editor:**

**Improve this sample solution and post your code through Disqus.**

**Previous:** Write a program in C to make such a pattern like a pyramid with a number which will repeat the number in the same row.

**Next:** Write a program in C to display the n terms of harmonic series and their sum.

**What is the difficulty level of this exercise?**

Test your Programming skills with w3resource's quiz.

## C Programming: Tips of the Day

**Clearing a char array c **

It depends on how you want to view the array. If you are viewing the array as a series of chars, then the only way to clear out the data is to touch every entry. memset is probably the most effective way to achieve this.

On the other hand, if you are choosing to view this as a C/C++ null terminated string, setting the first byte to 0 will effectively clear the string.

Ref : https://bit.ly/3uM7JnL

**Exercises: Weekly Top 12 Most Popular Topics**- Pandas DataFrame: Exercises, Practice, Solution
- Conversion Tools
- JavaScript: HTML Form Validation
- SQL Exercises, Practice, Solution - SUBQUERIES
- C Programming Exercises, Practice, Solution : For Loop
- Python Exercises, Practice, Solution
- Python Data Type: List - Exercises, Practice, Solution
- C++ Basic: Exercises, Practice, Solution
- SQL Exercises, Practice, Solution - exercises on Employee Database
- SQL Exercises, Practice, Solution - exercises on Movie Database
- SQL Exercises, Practice, Solution - exercises on Soccer Database
- C Programming Exercises, Practice, Solution : Recursion