c中的十进制算法的二进制给出奇怪的结果

Question

嗨，我相当新的c，但我正在写一个程序，我需要将二进制字符串转换为十进制数字。这里是我当前的代码：

int BinaryToInt(char *binaryString) 
{ 
    int decimal = 0; 
    int len = strlen(binaryString); 
    for(int i = 0; i < len; i++) 
    { 

     if(binaryString[i] == '1') 
      decimal += 2^((len - 1) - i); 
     printf("i is %i and dec is %i and the char is %c but the length is %i\n", i, decimal, binaryString[i], len); 
    } 
    return decimal; 
} 

int main(int argc, char **argv) 
{ 
    printf("%i", BinaryToInt("10000000")); 
} 

这里是输出：

i is 0 and dec is 5 and the char is 1 but the length is 8 
i is 1 and dec is 5 and the char is 0 but the length is 8 
i is 2 and dec is 5 and the char is 0 but the length is 8 
i is 3 and dec is 5 and the char is 0 but the length is 8 
i is 4 and dec is 5 and the char is 0 but the length is 8 
i is 5 and dec is 5 and the char is 0 but the length is 8 
i is 6 and dec is 5 and the char is 0 but the length is 8 
i is 7 and dec is 5 and the char is 0 but the length is 8 
5 

我很困惑，为什么这是不行的，所有帮助是极大的赞赏。提前致谢！

PS：我已经习惯了这样的Java此刻Ç只是让我哭

Answer 1

的^操作不是幂，而是改为按位异或运算符。

如果要将数字提高到2的幂，请使用左移运算符<<将1的值移动有问题的指数。

decimal += 1 << ((len - 1) - i); 

Answer 2

诀窍与任何数字基数相同：对于每个传入数字，将累加器乘以数字基数并添加数字。

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

int BinaryToInt(char *binaryString) 
{ 
    int decimal = 0; 
    int len = strlen(binaryString); 
    for(int i = 0; i < len; i++) { 
     decimal = decimal * 2 + binaryString[i] - '0'; 
    } 
    return decimal; 
} 

int main(void) 
{ 
    printf("%d", BinaryToInt("10000000")); 
    return 0; 
} 

程序输出：

128