# Simple C programming for gaussian

1. Oct 6, 2014

### darwinharianto

1. The problem statement, all variables and given/known data

make a gaussian elimination in C
the one we used on matrix to find x1 x2 and x3
if the matrix is 3x3
2. Relevant equations

3. The attempt at a solution

Code (Text):

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()
{
int i,j,k,n;
float A[3][4]={{3,0,6,1},{4,1,3,2},{6,3,0,3}};
float x[3],c,sum=0;
n=2;
for(i=0; i<=n; i++);
{
for(j=0; j<=n+1; j++);
{
if(i>j);
{
c=A[i][j]/A[j][j];
for(k=0; k<=n+1; k++);
{
A[i][k]=A[i][k]-A[j][k]*c;
}
}
}
}
x[n]=A[n][n+1]/A[n][n];
for(i=n-1; i>=0; i--);
{
sum=0;
for(j=i+1; j<=n; j++);
{
sum=sum+A[i][j]*x[j];
}
x[i]=(A[i][n+1]-sum)/A[i][i];
}
printf("\nThe solution is: \n");
for(i=0; i<=n; i++);
{
printf("\nx%d=%f\t",i,x[i]);
}
return(0);
}

at the end, only x0 and x1 displayed as the solution
should be x0 x1 and x2 right?
and the result

x0=-784.191895

x1=0.000000

seems to be incorrect
anything that i did wrong?
[/I][/I][/I][/I][/I][/I][/I][/I][/I]

Last edited: Oct 6, 2014
2. Oct 6, 2014

### Staff: Mentor

Can you edit your post to use the [ code ] tags?

They will preserve your code indentation without the need for an attachment.

3. Oct 6, 2014

### darwinharianto

how do i do that?
still new in this area

4. Oct 6, 2014

### phinds

put [C O D E] in front of your code and [/ C O D E] after it (but do NOT include the spaces in the tags. I had to insert them to keep this post from looking like code and hiding the tags.

5. Oct 6, 2014

### darwinharianto

ok
thanks
just like that right?

6. Oct 6, 2014

### SteamKing

Staff Emeritus
Make a 'gaussian' what in C? Your problem statement is a little vague.

7. Oct 6, 2014

### darwinharianto

gaussian elimination in matrix
sorry its not so clear

8. Oct 7, 2014

### darwinharianto

problem solved
by removing ; after for and if