c语言输入补码输出十进制怎么写代码

在C语言中，处理补码并将其转换为十进制通常涉及到从二进制表示开始。下面是一个简单的示例，展示如何读取一个整数的补码表示，并转换成对应的十进制值：

#include <stdio.h>
#include <inttypes.h>

// Function to convert a two's complement binary number to decimal
int convert_to_decimal(intptr_t num) {
    if (num == 0) return 0;
    int sign = num >> 31; // Extract the sign bit
    uint32_t absolute_num = num & ~((1 << 31) - 1); // Remove the sign and get the absolute value

    int decimal = 0;
    int power = 0;
    while (absolute_num != 0) {
        decimal += (absolute_num & 1) * pow(2, power);
        absolute_num >>= 1;
        power++;
    }

    return sign ? -decimal : decimal; // Apply the sign based on the original number being negative or positive
}

int main() {
    printf("Enter a two's complement integer in binary (in hexadecimal format): ");
    char input[4];
    scanf("%hhx", input); // Read input as hexadecimal (since we're working with bytes)

    // Convert hexadecimal to an int (assuming little-endian)
    intptr_t num = strtol(input, NULL, 16);

    int decimal_value = convert_to_decimal(num);
    printf("The decimal equivalent is: %d\n", decimal_value);

    return 0;
}

这个程序首先提取补码的符号位，然后将绝对值部分按位移除并逐位加到`decimal`变量上，最后根据原始数值的符号返回结果。