finding arc length of a curve

[cayvesigara]

hi guys, I just wrote the below code, but matlab gives me the different result. what is the problem with the below code? I need your comments. Thanks in advance


#include<stdio.h>
#include<conio.h>
#include<math.h>
void main(){
int i;
long double y[20000],yder[20000],t,syder[20000],sumx;
for(i=1,t=1;i<=10001,t<=2;i=i+1,t=t+0.0001){
y[i]=((1/6)*pow(t,3))+(0.5/t);}
for(i=1;i<=10000;i++){
yder[i]=(y[i+1]-y[i])/0.0001;
}
for(i=1;i<=10000;i++){
syder[i]=pow(1+(yder[i]*yder[i]),0.5);}
sumx=0;
for(i=1;i<=10000;i++){
sumx=sumx+((syder[i]+syder[i+1])*0.0001/2);
}
printf("\n%Lf",sumx);
getch();
}

[weaknessforcats]

It looks like the type of t is int so t=t+0.0001 won't work.

Also 1/6 is always 0. There are no sixes in 1. Maybe try 1.0/6.0 to tell the compiler to use floating point division instead of integer division.

Never mix integer and floating point. It's all floating point or all integer. Otherwise these creepy discrepancies will pop up as the compiler tries to figure out what you want. Like ,t=t+0.0001 causes t to be converted to a double, the .0001 is added to a sum which is double. Then the sum is truncated back to int to stuff it back in t. You should be getting a warning about truncation and possible loss of data.