c语言实现将16进制字符串80转换为二进制

在C语言中，你可以通过遍历十六进制字符串并将其转换为对应的四位二进制数来实现这个过程。这里是一个简单的示例函数，它接受一个十六进制字符串作为输入，并返回其二进制表示：

#include <stdio.h>
#include <string.h>

// 函数用于将16进制字符串转换为二进制字符串
void hex_to_binary(char *hex_str, char *binary_out) {
    int len = strlen(hex_str);
    for (int i = 0; i < len; i++) {
        // 检查字符是否为有效的十六进制数字
        if ('0' <= hex_str[i] && hex_str[i] <= '9') {
            binary_out[i * 4] = hex_str[i] - '0';
            binary_out[i * 4 + 1] = hex_str[i] + 8;
            binary_out[i * 4 + 2] = hex_str[i] + 16;
            binary_out[i * 4 + 3] = hex_str[i] + 24;
        } else if ('A' <= hex_str[i] && hex_str[i] <= 'F') {
            binary_out[i * 4] = hex_str[i] - 'A' + 10;
            binary_out[i * 4 + 1] = hex_str[i] + 10 - 8;
            binary_out[i * 4 + 2] = hex_str[i] + 10 - 16;
            binary_out[i * 4 + 3] = hex_str[i] + 10 - 24;
        } else if ('a' <= hex_str[i] && hex_str[i] <= 'f') {
            binary_out[i * 4] = hex_str[i] - 'a' + 10;
            binary_out[i * 4 + 1] = hex_str[i] + 10 - 8;
            binary_out[i * 4 + 2] = hex_str[i] + 10 - 16;
            binary_out[i * 4 + 3] = hex_str[i] + 10 - 24;
        } else {
            printf("Invalid character in hexadecimal string.\n");
            return;
        }
    }
    binary_out[len * 4] = '\0';  // 添加终止符
}

int main() {
    char hex_str[] = "80";
    char binary[8];  // 足够容纳最多两位十六进制对应8位二进制
    hex_to_binary(hex_str, binary);
    printf("Hexadecimal %s is binary %s\n", hex_str, binary);
    return 0;
}

在这个例子中，`hex_to_binary`函数会把每个十六进制字符转换为四个二进制位，然后拼接成新的二进制字符串。