’表达式必须是指向完整对象类型的指针‘是怎么回事

#include<iostream>
#include<string>
using namespace std;

typedef char VerTexType;
typedef int ArcType;

#define MVNum 100
#define MaxInt 32767

struct {
    VerTexType adjvex; 
    ArcType lowcost;
}closedeg[MVNum];

typedef struct {
    VerTexType vexs[MVNum];         //顶点表 
    ArcType arcs[MVNum][MVNum];     //邻接矩阵 
    int vexnum, arcnum;             //图的当前点数和边数 
}AMGraph;


//确定v在G中的位置
int LocateVex(AMGraph G, VerTexType v)
{
    int i;
    for (i = 0; i < G.vexnum; i++)
        if (v == G.vexs[i])
            return i;
    return -1;
}


//创建无向网
void CreateUDN(AMGraph& G)
{

    char v1, v2;
    int w, m, n;

    cin >> G.vexnum >> G.arcnum;//输入顶点与边数量
    
    for (int i = 0; i < G.vexnum; i++)//输入顶点信息
        cin >> G.vexs[i];

    for (int i = 0; i < G.vexnum; i++)//初始化矩阵
        for (int j = 0; j < G.vexnum; j++)
            G.arcs[i][j] = MaxInt;

    for (int k = 0; k < G.arcnum; k++)
    {
        cin >> v1 >> v2 >> w;
        m = LocateVex[G, v1];


    }

}

咋回事呀

m = LocateVex[G, v1];
改为
m = LocateVex(G, v1);
你这是函数调用啊！！怎么写中括号呢