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How to convert char array of 64 bytes to long long int

This is a discussion on How to convert char array of 64 bytes to long long int within the C Programming forums, part of the General Programming Boards category; Here's an extension of the original program I gave. Choose an "endianness" and copy the key.ints into the rd_key of ...

  1. #16
    - - - - - - - - oogabooga's Avatar
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    Here's an extension of the original program I gave. Choose an "endianness" and copy the key.ints into the rd_key of your struct.
    Code:
    #include <stdio.h>
    
    //#define METHOD_ONE
    
    int main() {
        char dek[] = "016211c7f60824a8ec5df54737a08ad0"
                     "a11b2e451160601a94ccd53555a335ab";
        union {
            unsigned char bytes[32];
            unsigned int  ints[8];
        } key;
        unsigned x;
        int i, j;
    
    #ifdef METHOD_ONE
        for (i = 0; i < 32; i++) {
            sscanf(dek+i*2, "%2x", &x);
            key.bytes[i] = x;
        }
    #else
        for (i = 0; i < 8; i++)
            for (j = 0; j < 4; j++) {
                sscanf(dek+(i*4+j)*2, "%2x", &x);
                key.bytes[i*4+3-j] = x;
            }
    #endif
    
        // Print string
        printf("%s\n", dek);
    
        // Print bytes
        for (i = 0; i < 32; i++) printf("%02x", key.bytes[i]);
        printf("\n");
    
        // Print ints
        for (i = 0; i < 8; i++) printf("%08x", key.ints[i]);
        printf("\n");
    
        return 0;
    }

  2. #17
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    i think i am getting it... will try and get back to the forum.. thanks a lot oogabooga and also to other users who have replied...

  3. #18
    - - - - - - - - oogabooga's Avatar
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    Actually, I've made the above code too complicated. You want something more like this:
    Code:
    void hexStringToUIntArray(char *str, unsigned *a) {
        int i;
        for (i = 0; i < 8; i++)
            sscanf(str + i * 8, "%8x", &a[i]);
    }
    
    int main() {
        char dek[] = "016211c7f60824a8ec5df54737a08ad0"
                     "a11b2e451160601a94ccd53555a335ab";
        unsigned a[8];
        int i;
    
        hexStringToUIntArray(dek, a);
    
        // Print string
        printf("%s\n", dek);
    
        // Print ints
        for (i = 0; i < 8; i++) printf("%08x", a[i]);
        printf("\n");
    
        return 0;
    }

  4. #19
    Registered User
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    Dec 2005
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    134
    Try this to convert string in long:
    Code:
    int main()
    {
    long long var;
    char p[]="cboard";
    var = atoll(p);
    return 0;
    }
    long long atoll(char *str)
    {
            long long num1;
            sscanf(str,"%llu",&num1);
            return num1;
    }
    S_ccess is waiting for u. Go Ahead, put u there.

  5. #20
    C++ Witch laserlight's Avatar
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    Singapore
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    maven: atoll is already in the standard library (per C99), and you would probably have better luck suggesting strtoll instead due to base conversion.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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