有没有大佬告诉我这个函数为甚么放在main（）里就能运行 但是在子函数里运行就有偏差

Question

#include<stdio.h>#include <stdlib.h>int *wuli(int *pa, int a,int *pb,int b){      int *pc = (int *)malloc(sizeof(int)*(a + b)); for (int i = 0; i < a; i++) {   pc [i]= pa[i];    } for (int i = 0; i < b; i++) {  pc[i+a] = pb[i]; } return *pc;}void main(){ int a, b; printf("a的长度是多少 "); scanf("%d", &a); int *pa = malloc(sizeof(int)*a); for (int i = 0; i < a; i++) {   scanf("%d",& pa[i]);   }  printf("b的长度是多少 "); scanf("%d", &b); int *pb = malloc(b*sizeof(int)); for (int i = 0; i < b; i++) {  scanf("%d", &pb[i]); }  int *p=wuli(&pa, a, &pb, b);  for (int i = 0; i < a + b; i++) {  printf("%d", p[i]); } system("pause");}