将char字符串解析为INT C编程

Question

I'm trying to parse a char string into an INT.

If I had...

unsigned char color[] = "255"

And wanted to parse this into an INT. How would I go about doing this?

I tried...

unsigned char *split;

split = strtok(color," ,.-");
while(split != NULL)
{
    split = strok(NULL, " ,.-);
}

This just gives me the value 255 for split now.

I feel like I need something like...

int y = split - '0';   //but this makes an INT pointer without a cast

Answer 1

To convert a string to integer, call strtol :

char color[] = "255";
long n;
char *end = NULL;
n = strtol(color, &end, 10);
if (*end == '\0') {
    // convert was successful
    // n is the result
}

Answer 2

If you want to convert without calling strtol you can scan the color array and compare each char against '0' to get the corresponding numeric value, then add the result properly multiplied by a power of 10, ie

int i = 0, strlen = 0, result = 0;
while (color[i++]) strlen++;
for (i = 0; i<strlen; i++)
{
    result += (color[i] - '0')*pow(10,strlen-1-i);
}