[root@lex tst]# cat gao3.c
#include <stdio.h>
#include <string.h>

char * function1 (char *p)
{
  printf("In function1 %s\n",p);
  return p;
}

char * function2 (char *p)
{
  printf("In function2 %s\n",p);
  return p;
}

char * function3 (char *p)
{
  printf("In function3 %s\n",p);
  return p;
}

int main()
{

  char * (*pf[3]) (char *p);

  pf[0] = function1;
  pf[1] = &function2;
  pf[2] = &function3;

  pf[0]("func1");
  pf[1]("func2");
  pf[2]("func3");

  return 0;
}
[root@lex tst]# 

[root@lex tst]# gcc -o gao3 gao3.c
[root@lex tst]# ./gao3
In function1 func1
In function2 func2
In function3 func3
[root@lex tst]#