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如何使用指针初始化和打印结构并将其提供给函数?

[英]How can i initialize and print out a Structure with a pointer and give it to a function?

我想打印出一个带有指针的结构并将其赋予另一个函数。

我的问题是:如何使用变量名称“注册”来初始化结构并将其打印出来以测试并查看我的值和地址? 我的程序目标基本上是模拟 CPU。 因此,我有 3 个指向订单、堆栈和计算器的指针(这是我们老师给的任务)。 但我不太擅长结构和指针

#include<stdio.h>
#include<stdint.h>
#include<stdbool.h>

struct reg {
  unsigned char pc; // Befehlszeiger
  unsigned char sp; // Stapelzeiger
  unsigned char fa; // Flags + Akkumulator
};

bool cpu(struct reg *registers, unsigned char data[128], uint16_t cmd[256]);


int main(){
unsigned char data[128];
uint16_t cmd[256];
cmd[127] = 12;
data[127] = 'D';
data[128] = 'Z';
struct reg *registers = { '1', '2', '3'};
printf("The number before function: %d\n", registers->pc);
cpu(registers, data, cmd);
return 0;
}

bool cpu(struct reg *registers, unsigned char data[128], uint16_t cmd[256])
{
printf("The number in function: %d\n", registers->pc);
return 0;
}

因为程序说:

|20|warning: initialization makes pointer from integer without a cast [-Wint-conversion]|
20|note: (near initialization for 'registers')|
20|warning: excess elements in scalar initializer|
|20|note: (near initialization for 'registers')|
c|20|warning: excess elements in scalar initializer|
c|20|note: (near initialization for 'registers')|

要使其工作,请按如下方式重写代码:

struct reg registers = { '1', '2', '3'};  // "registers" isn't a pointer
printf("The number before function: %d\n", registers.pc); // "." instance of a struct
cpu(&registers, data, cmd);// pass the address of "registers"

如果你想要内存的动态分配,你可以这样做:

#include<stdio.h>
#include<stdint.h>
#include<stdbool.h>
#include<stdlib.h>

struct reg {
  unsigned char pc; // Befehlszeiger
  unsigned char sp; // Stapelzeiger
  unsigned char fa; // Flags + Akkumulator
};

bool cpu(struct reg *registers, unsigned char data[128], uint16_t cmd[256]);


int main(){
unsigned char data[128];
uint16_t cmd[256];
cmd[127] = 12;
data[127] = 'D';
data[128] = 'Z';
struct reg *registers;
registers = (struct reg*)malloc(sizeof(struct reg));
registers->pc = '1';
registers->sp = '2';
registers->fa = '3';

printf("The number before function: %d\n", registers->pc);
cpu(registers, data, cmd);
if(registers){
    free(registers);
}
return 0;
}

bool cpu(struct reg *registers, unsigned char data[128], uint16_t cmd[256])
{
printf("The number in function: %d\n", registers->pc);
return 0;
}

否则,如果您不需要动态分配内存:

#include<stdio.h>
#include<stdint.h>
#include<stdbool.h>

struct reg {
  unsigned char pc; // Befehlszeiger
  unsigned char sp; // Stapelzeiger
  unsigned char fa; // Flags + Akkumulator
};

bool cpu(struct reg *registers, unsigned char data[128], uint16_t cmd[256]);


int main(){
unsigned char data[128];
uint16_t cmd[256];
cmd[127] = 12;
data[127] = 'D';
data[128] = 'Z';
struct reg registers = { '1', '2', '3'};
printf("The number before function: %d\n", registers.pc);
cpu(&registers, data, cmd);
return 0;
}

bool cpu(struct reg *registers, unsigned char data[128], uint16_t cmd[256])
{
printf("The number in function: %d\n", registers->pc);
return 0;
}

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