# C Program to Find Sum of Geometric Progression Series

Find the sum of GP or geometric progression series in the c program; Through this tutorial, we will learn how to find sum of GP series or geometric progression series using formula, for loop and function in c programs.

## Programs to Find Sum of Geometric Progression Series in C

• C Program to Find Sum of Geometric Progression Series using Formula
• C Program to Find Sum of Geometric Progression Series using For Loop
• C Program to Find Sum of Geometric Progression Series using Function

### C Program to Find Sum of Geometric Progression Series using Formula

```/* C Program to find Sum of Geometric Progression Series */
#include <stdio.h>
#include<math.h>
int main() {

int a, n, r;
float tn, sum = 0;

printf(" Please Enter First Number of an G.P Series:  ");
scanf("%d", &a);
printf(" Please Enter the Total Numbers in this G.P Series:  ");
scanf("%d", &n);
printf(" Please Enter the Common Ratio:  ");
scanf("%d", &r);

sum = (a * (1 - pow(r, n ))) / (1- r);
tn = a * (pow(r, n - 1));

printf("\n The Sum of Geometric Progression Series =  %.2f", sum);
printf("\n The tn Term of Geometric Progression Series = %.2f \n", tn);
return 0;
}
```

The output of the above c program; is as follows:

```Please Enter First Number of an G.P Series:  1
Please Enter the Total Numbers in this G.P Series:  5
Please Enter the Common Ratio:  2
The Sum of Geometric Progression Series =  31.00
The tn Term of Geometric Progression Series = 16.00 ```

### C Program to Find Sum of Geometric Progression Series using For Loop

```/* C Program to find Sum of Geometric Progression Series */
#include <stdio.h>
#include<math.h>
int main() {

int a, n, r, value, i;
float sum = 0;

printf(" Please Enter First Number of an G.P Series:  ");
scanf("%d", &a);
printf(" Please Enter the Total Numbers in this G.P Series:  ");
scanf("%d", &n);
printf(" Please Enter the Common Ratio:  ");
scanf("%d", &r);

value = a;
printf("G.P Series  :  ");
for(i = 0; i < n; i++)
{
printf("%d  ", value);
sum = sum + value;
value = value * r;
}
printf("\n The Sum of Geometric Progression Series =  %f\n", sum);
return 0;
}
```

The output of the above c program; is as follows:

```Please Enter First Number of an G.P Series:  2
Please Enter the Total Numbers in this G.P Series:  5
Please Enter the Common Ratio:  2
G.P Series  :  2  4  8  16  32
The Sum of Geometric Progression Series =  62.000000```

### C Program to Find Sum of Geometric Progression Series using Function

```/* C Program to find Sum of Geometric Progression Series */
#include <stdio.h>
#include<math.h>
int sumofGP(int a, int n, int r)
{
int sum = (a * (1 - pow(r, n))) / (1- r);
return sum;
}

int main() {

int a, n, r;
float sum = 0;

printf(" Please Enter First Number of an G.P Series:  ");
scanf("%d", &a);
printf(" Please Enter the Total Numbers in this G.P Series:  ");
scanf("%d", &n);
printf(" Please Enter the Common Ratio:  ");
scanf("%d", &r);

sum = sumofGP(a, n, r);
printf("\n The Sum of Geometric Progression Series =  %f\n", sum);
return 0;
}
```

The output of the above c program; is as follows:

```Please Enter First Number of an G.P Series:  2
Please Enter the Total Numbers in this G.P Series:  5
Please Enter the Common Ratio:  2
The Sum of Geometric Progression Series =  62.000000``` 