Modify Bytes in a 32-bit Value Using Union

Code

#include <stdio.h>
#include <stdint.h>

typedef union {
    uint32_t value;
    uint8_t bytes[4];
} Register;

// Write logic here using union to modify byte[1] and byte[2]
void modify_and_print(uint32_t input, uint8_t b1, uint8_t b2) {
    // Your logic here
    Register reg;
    
    reg.value = input;
    reg.bytes[0] = (uint8_t)input;
    reg.bytes[1] = (uint8_t)(input>>8);
    reg.bytes[2] = (uint8_t)(input>>16);
    reg.bytes[3] = (uint8_t)(input>>24);
    reg.bytes[1] = b1;
    reg.bytes[2] = b2;
    uint32_t recon = 0;
    recon |= reg.bytes[0];
    recon |= reg.bytes[1]<<8;
    recon |= reg.bytes[2]<<16;
    recon |= reg.bytes[3]<<24;
    printf("%ld", recon);

}

int main() {
    uint32_t num;
    uint8_t b1, b2;
    scanf("%u %hhu %hhu", &num, &b1, &b2);
    modify_and_print(num, b1, b2);
    return 0;
}

Solving Approach

 

 

 

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Input

305419896 170 187

Expected Output

314288760