在C中创建和写入多个txt文件

I've got a code which creates j files (Node[j].ID) in a directory called (Nodes) and in those j files the code writes the info contained in NodeResults. At the moment the code doesn't neither create nor write in files because of the strcat function doesn't work. Please any idea how to correct the code in order to get the created files with the info contained in NodeResults on it?. Thanks in advance. Please find the code below:I've got a code which creates j files (Node[j].