Pcanal ,please help me?？？

ROOT
1

too much colum how to fill tree
i have data that is made of 131 column, the first column is time,the other is data.So i want to draw each of the data vs time. I want to use tree.

FILE *fp;
fp=fopen(“data.txt”,“r”);
float column[131];
TTree *tree=new TTree(“tree”,“data from ascii file”);
tree->Branch(“column[0]”,&column[0],“column[0]/F”);
tree->Branch(“column[1]”,&column[1],“column[1]/F”);
……
tree->Branch(“column[130]”,&column[130],“column[130]/F”);

while(!feof(fp))
{
fscanf(fp,"%f %f %f……“，&column[0],&column[1],……,&column[130]);
tree->Fill();
}
it is so diffcult to write 130 branch and fscanf(fp,"%f %f %f……“，&column[0],&column[1],……,&column[130]);
please tell me if there is a easy way ?
for example loop?

2

What is the problem? What are the error messages? Which version of ROOT are you using? Did you try compiling your code (with ACLiC for example)?
Did you try TTree::ReadFile?

Cheers,
Philippe

3

[quote=“pcanal”]What is the problem? What are the error messages? Which version of ROOT are you using? Did you try compiling your code (with ACLiC for example)?
Did you try TTree::ReadFile?

Cheers,
Philippe[/quote]
130 Column,I must write 130 branches,it is so diffcult.
LOOP ?
for(i=0;i<130>Branch(“column[i]”,&column[i],“column[i]/F”);
ok?
Thanks!
TTree::ReadFile?
It must write 130 variables .I can’t bear.
Loop can do it?

4

Please disable the HTML in your post when copy pasting code.

Nonetheless, your code would work with the following tweak:tree->Branch(Form("column_%d",&column[i],"column_%d/F"); Cheers,
Philippe

5

[quote=“pcanal”]Please disable the HTML in your post when copy pasting code.

Nonetheless, your code would work with the following tweak:tree->Branch(Form("column_%d",&column[i],"column_%d/F"); Cheers,
Philippe[/quote]

what is the meaning of Form?

6

tree->Branch(Form(“column_%d”,&column[i],“column_%d/F”);

why there is a “{”, please tell me why i can’t run my programm?
fq.txt (5.74 KB)
plot.c (740 Bytes)

7

My apologies for the typo. I meant:

Philippe