error C2275: 'FILE' : illegal use of this type as an expression

//头部定义

FILE *outfile1;
FILE *outfile2;

//函数引用
outfile1=fopen("out.txt","w");
    for(j=0;j<SIZE;j++){
                
        p=graph.adjlist[j].FirstEdge;
        while(p!=NULL){
            fprintf(outfile1," %d %d",j,p->adjvex);
            p=p->next;
        }
这样就解决了！