c - 在嵌入式 C 中显示 "expected expression before while"

Question

考虑:

#include <avr/io.h>

int main(void)
{
    DDRB = 0b11111111; // PORTB as output port connected to motors;
    DDRC = 0b0000000; // PORTC Input port connected to sensors;
    int left_sensor = 0;
    int right_sensor = 0;
    while(1)
    {
        left_sensor = PINC&0b00000001;
        right_sensor = PINC&0b00001000;
        if((left_sensor==0b0000000) && (right_sensor==0b0000000))
        {
            PORTB = 0b00000000;
        }
        else if((left_sensor==0b00000001) && (right_sensor==0b00001000))
        {
            PORTB = 0b00010010;
        }
        else if((left_sensor==0b0000000) && (right_sensor==0b0001000))
        {
            PORTB = 0b00000010;
        }
        else if((left_sensor==0b00000001) && (right_sensor==0b0000000))
        {
            PORTB = 0b00010000;
        }
    }
}

它显示“while 之前的预期表达式”。我已经尝试了一切，但没有得到任何解决方案。

错误:

Expected Expression before 'while'

编译器:Atmel Studio 7

Answer 1

如果我复制并粘贴您问题中的代码，请删除 AVR 特定行并尝试编译它，我会得到以下结果:

source_file.c: In function ‘main’:
source_file.c:4:10: error: stray ‘\315’ in program
          int right_sensor=0;
          ^
source_file.c:4:10: error: stray ‘\276’ in program
source_file.c:5:10: error: expected ‘,’ or ‘;’ before ‘while’
          while(1)
          ^

删除带有 right_sensor 声明的行并重写它可以解决问题 - 该行中似乎有一些奇怪的非打印字符。