# Why does my code not work? [closed]

Why does the following code not work?

t=1;h=0.1;n=t/h+1;m=3;
W=Table[0,{n},{m+1}];
for[k=2,k<m+1,k++,
f=Table[0,{n-2},{n-2}];
f[[1,1]]=2-1/(1+10*h)+10*h*h*W[[2,k]];f[[1,2]]=-1+5*h;
for[i=2,i<n-2,i++,
f[[i,i]]=2+10*h*h*W[[i+1,k]];
f[[i,i-1]]=-1-5*h;
f[[i,i+1]]=-1+5*h;];
f[[n-2,n-2]]=5*h+1+10*h*h*W[[n-1,k]];
f[[n-2,n-3]]=-1-5*h;
F=Table[0,{n-2}];
for[i=1,i<n-1,i++,
F[[i]]=
-W[[i+2,k]]+2*W[[i+1,k]]-W[[i,k]]+
5*h*(W[[i+2,k]-W[[i,k]])+
5*h*h*W[[i+1,k]]*W[[i+1,k]];];

A=Linear Solve[f,-F];
for[i=2,i<n,i++,
W[[i,k+1]]=W[[i,k+1]]+A[[i]]];
W[[1,k+1]]=(W[[2,k+1]]+50*h)/(10*h+1);
W[[n,k+1]]=W[[n-1,k+1]]];

• 1) please format your code, add line breaks, and indent it for readability. 2) For should be uppercase 3) you should avoid For loops. Dec 10 '19 at 2:43
• There are syntax errors in your code. Use For not for; LinearSolve not Linear Solve; and there is a extra ] in last For-loop. Dec 10 '19 at 5:03
• F comes out as {0, 0, 0, 0, 0, 0, 0, 0, 0} because there is no code to populate W, Dec 10 '19 at 5:20
• In the last inner For-loop, (W[[i + 2, k] - W[[i, k]]) should be (W[[i + 2, k]] - W[[i, k]]) Dec 10 '19 at 5:25

This may be a partial answer. As I understand it your elaborate calculation of f can be replaced with:
t = 1;