变量声明冲突，类型重新声明

Question

我有这些错误和警告...我对编程很陌生，我不知道这意味着什么。你们能看看这个并告诉我我做错了什么吗？

提前致谢

错误和警告:

Looplicht v2.0.c:226: warning: (361) function declared implicit intLooplicht v2.0.c:237: error: (984) type redeclaredLooplicht v2.0.c:237: error: (1098) conflicting declarations for variable "integer_reverse" (Looplicht v2.0.c:237)

code with errors (I have placed the linenumbers of the errors in the description):

void mode_single_right() {

output_integer = 0x0001;        //start right

    for (unsigned char i = 0; i < number_of_outputs; i++) {
        if (jump) {
            jump = 0;
            
            output_integer = integer_reverse(output_integer);       //line 226
            switch_outputs(output_integer);                         
            output_integer = (output_integer << 1);                 
        } else {
            i--;
        }
    }


}

unsigned int integer_reverse (unsigned int input_br) {          //line 237

unsigned int output_br = 0;
bit bit_in_reverse = 0;

for (unsigned char ibr = 0; ibr < 16; ++ibr) {

    bit_in_reverse = input_br & 0x01;
    output_br |= bit_in_reverse;
    input_br >>= 1;
    output_br <<= 1;
}
return output_br;
}

Answer 1

您应该在调用函数之前声明它。在第 226 行之前的某个位置(最好是在任何函数之外)，包含一个原型(prototype):

unsigned int integer_reverse( unsigned int input_br );

如果调用未声明的函数，在 C89 中，编译器假定声明为:

int integer_reverse();

然后它遇到你的函数头(它是原型(prototype)格式，所以它算作一个原型(prototype))并且编译器检测到这个原型(prototype)与你原来的隐式声明不兼容。