Construct UART Data Frame with Parity Bit

Code

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

typedef struct {
    uint8_t parity_enable : 1;
    uint8_t parity_type   : 1;
    uint8_t reserved      : 6;
} UART_Control;

uint8_t count_ones(uint8_t data){
    uint8_t count = 0;
    while (data){
        data = data & (data - 1);
        count++;
    }
    return count;
}
uint8_t create_uart_frame(uint8_t data, UART_Control *ctrl) {
    // Your logic here
    if (ctrl->parity_enable == 0) {
        // parity disabled
        return data;
    }

    uint8_t ones = count_ones(data);

    if ((ctrl->parity_type == 0) && ((ones % 2) != 0)) {
        data |= (1 << 7);
    }

    if ((ctrl->parity_type == 1) && ((ones % 2) == 0)) {
        data |= (1 << 7);
    }
    
    return data;
}

int main() {
    uint8_t data;
    scanf("%hhu", &data);  // 7-bit input

    uint8_t parity_enable, parity_type;
    scanf("%hhu %hhu", &parity_enable, &parity_type);

    UART_Control ctrl;
    ctrl.parity_enable = parity_enable;
    ctrl.parity_type = parity_type;

    uint8_t frame = create_uart_frame(data, &ctrl);
    printf("frame = 0x%02X", frame);

    return 0;
}

Solving Approach