Approximate the value of PI

[RandiHoltermann]

Hi guys. I’m pretty new to C program. I’ve been given this assignment to write a program that asks the user thow many terms of the serires equation to use in approximating PI. The formula given is pi=4X(1- 1/3 + 1/5 – 1/7 + 1/9 – 1/11 + 1/13 – ….)

Here is the script that I’ve written but I’m stuck. Please advice. My alogarithm might be wrong

#include <stdio.h><br /> int main (void)<br /> {<br /> int x,<br /> i;<br /> //int sum=0;<br /> double PI;<br /> float sum=0, y;<br /> <br /> printf("Please enter the terms of series that should be included> ");<br /> scanf("%d", &#038;x);<br /> <br /> for (i=1; i<=x; i++){<br /> i=y;<br /> <br /> if (i%2==1) //odd<br /> <br /> if (sum%2==0)<br /> sum=sum+1/y;<br /> else<br /> sum=sum-1/y;<br /> }<br /> <br /> PI= 4*sum;<br /> printf("The sum is %fn", sum);<br /> printf("Approximate value of PI is %fn", PI);<br /> <br /> return 0;<br /> }<br />

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#include <stdio.h><br /> int main (void)<br /> {<br /> int x,<br /> i;<br /> //int sum=0;<br /> double PI;<br /> float sum=0, y;<br /> <br /> printf("Please enter the terms of series that should be included> ");<br /> scanf("%d", &#038;x);<br /> <br /> for (i=1; i<=x; i++){<br /> i=y;<br /> <br /> if (i%2==1) //odd<br /> <br /> if (sum%2==0)<br /> sum=sum+1/y;<br /> else<br /> sum=sum-1/y;<br /> }<br /> <br /> PI= 4*sum;<br /> printf("The sum is %fn", sum);<br /> printf("Approximate value of PI is %fn", PI);<br /> <br /> return 0;<br /> }<br />

[glimpse]

I don’t understand so much from mathemics, but a problem migth be, that your variable i is an integer value.
Something else: What should happen, if (i%2==1) ?
I expect you mean the hole part:

<br /> if (sum%2==0)<br /> sum=sum+1/y;<br /> else    sum=sum-1/y;<br /> //The I would put this part into brackets {}.if (i%2==1){   <br /> if (sum%2==0)<br />         sum=sum+1/y;<br /> <br />     else<br />         sum=sum-1/y;orif (i%2==1)<br />     if (sum%2==0)<br />         sum=sum+1/y;else    sum=sum-1/y;<br />

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<br /> if (sum%2==0)<br /> sum=sum+1/y;<br /> else    sum=sum-1/y;<br /> //The I would put this part into brackets {}.if (i%2==1){   <br /> if (sum%2==0)<br />         sum=sum+1/y;<br /> <br />     else<br />         sum=sum-1/y;orif (i%2==1)<br />     if (sum%2==0)<br />         sum=sum+1/y;else    sum=sum-1/y;<br />

[RandiHoltermann]

Thanks for your input. The following is the working scripts

#include <stdio.h><br /> int main (void)<br /> {<br /> int x;<br /> float sum=0;<br /> double PI;<br /> <br /> printf("Please enter the terms of series that should be included> ");<br /> scanf("%d", &#038;x);<br /> <br /> for (int i=1; i<x; i+=2)<br /> if (i%4==1)<br /> sum=sum+1./(double)i;<br /> else<br /> sum=sum-1./(double)i;<br /> <br /> PI= 4*sum;<br /> printf("The sum is %fn", sum);<br /> printf("Approximate value of PI is %fn", PI);<br /> <br /> return 0;<br /> }

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#include <stdio.h><br /> int main (void)<br /> {<br /> int x;<br /> float sum=0;<br /> double PI;<br /> <br /> printf("Please enter the terms of series that should be included> ");<br /> scanf("%d", &#038;x);<br /> <br /> for (int i=1; i<x; i+=2)<br /> if (i%4==1)<br /> sum=sum+1./(double)i;<br /> else<br /> sum=sum-1./(double)i;<br /> <br /> PI= 4*sum;<br /> printf("The sum is %fn", sum);<br /> printf("Approximate value of PI is %fn", PI);<br /> <br /> return 0;<br /> }

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