编译器提示 “opcode_table undeclared (first use in this function)"，为什么？

Question

我有这个功能:

void run(int PC)
{
    int A = 0, op = 0, arg = 0, i = 0;
    char *xpress = NULL, *acode = NULL, strarg[CL_ARG_SIZE];
    while (1)
      {
        printf("PC: %03x | A: %03i |", PC, A);
        op = data[PC]; arg = data[PC+1];
        PC += 2;
        for (i=0 ; i<21 ; ++i)
             if (op == opcode_table[i].op)
             {
                 acode = opcode_table[i].mnemo;
                 sprintf(strarg, "0x%x", arg);   
                 xpress = replace(opcode_table[i].instruct, "_", strarg);
                 break;
              }
         printf(" %s %x\t| %s \t", acode, arg, xpress);
         step();
         exec_instruct(op, arg, &A, &PC);
    }
}

当我尝试编译我的程序时，出现以下错误:

:103:35: error:‘opcode_table’ undeclared (first use in this function) :103:35: note: each undeclared identifier is reported only once for each function it appears in

我做错了什么？

Answer 1

在您的函数中有三行代码，您在其中使用了数组变量 opcode_table 而没有先声明它。开始于:

if (op == opcode_table[i].op)