c - 执行一个将字符串从基数转换为 int 的函数

Question

我需要执行一个函数，将字符串从它提供给我们的基数转换为十进制数。

Ex : someone give me a string in base hexa and I need to make it decimal

我应该将字符在基数中的位置乘以幂乘以基数的长度吗？

类似这样的

Indexbase * ( lenghtbase^power)

然后我添加所有内容来完成我的号码？

Answer 1

您遵循此代码:

int hexadecimalToDecimal(char hexVal[]) 
{    
    int len = strlen(hexVal); 

    // Initializing base value to 1, i.e 16^0 
    int base = 1; 

    int dec_val = 0; 

    // Extracting characters as digits from last character 
    for (int i=len-1; i>=0; i--) 
    {    
        // if character lies in '0'-'9', converting  
        // it to integral 0-9 by subtracting 48 from 
        // ASCII value. 
        if (hexVal[i]>='0' && hexVal[i]<='9') 
        { 
            dec_val += (hexVal[i] - 48)*base; 

            // incrementing base by power 
            base = base * 16; 
        } 

        // if character lies in 'A'-'F' , converting  
        // it to integral 10 - 15 by subtracting 55  
        // from ASCII value 
        else if (hexVal[i]>='A' && hexVal[i]<='F') 
        { 
            dec_val += (hexVal[i] - 55)*base; 

            // incrementing base by power 
            base = base*16; 
        } 
    } 

    return dec_val; 
}