CODEWITHSUNDEEP
c
Nagi
Nagi

Reputation: 137

How can I change char array to int using C?

i am studying C now, and I am parsing a raw registry file and read it.

i have some problem now,

000011E0    00 00 00 00 60 01 00 00 B9 01 00 00 00 00 00 00 
000011F0    20 C0 26 00 FF FF FF FF 00 00 00 00 FF FF FF FF 
00001200    10 FC 00 00 FF FF FF FF 4C 00 01 00 00 00 00 00
this is hex value of REGISTRY file.

fseek(fp,0x11F0,SEEK_SET);

char tmp[4];
int now = ftell(fp);
for(int i = 0 ; i < 4 ; i++){
    tmp[i] = fgetc(fp);
    }

I made this tmp array, but I need 0x0026c020. how can I change this array to that value? or please suggest me better algorithm.

Thanks.

Upvotes: 0

Views: 156

Answers (2)

flying-high
flying-high

Reputation: 219

To convert a string into integer there are already available functions one such function is strtoul().

you can use standard strtoul() function to convert string into integer values.

Upvotes: 0

cdhowie
cdhowie

Reputation: 168988

If you know for a fact that the value is stored with the same endianness as the host OS architecture, you can just do:

int value = *(int *)tmp;

However, you should not read the bytes in backwards order, as you do here -- that alters the endianness and will result in an incorrect value. Try this:

int value;
if (fread(&value, sizeof(value), 1, fp) != 1) {
    /* Could not read, handle error. */
}

/* value is set, inspect it */

Upvotes: 2

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