soma.c

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

char* int_to_bin_str(unsigned int n) {
    int i;
    int mask = 1;
    char *str_n = (char*)malloc(32);

    for (i = 0; i < 32; i++) {
        if (mask & n)
            str_n[31-i] = '1';
        else
            str_n[31-i] = '0';
        mask = mask << 1;
    }

    return str_n;
}

unsigned int bin_str_to_int(char *n_str) {
    int i;
    unsigned int result = 0;
    unsigned int power = 1;

    for (i = 31; i >= 0; i--){
        if (n_str[i] == '1')
            result = result + power;
        power = power << 1;
    }
    return result;
}

int main(int argc, char** argv) {
    int i;
    unsigned int result;
    bool carry_one = false;
    char *result_str = (char*)malloc(32);

    char *n1 = int_to_bin_str(10);
    char *n2 = int_to_bin_str(11);

    for (i = 31; i >= 0; i--) {
        if (n1[i] == '0' && n2[i] == '0') {
            if (carry_one == true) {
                result_str[i] = '1';
                carry_one = false;
            } else {
                result_str[i] = '0';
            }
        }

        if ((n1[i] == '1' && n2[i] == '0') || (n1[i] == '0' && n2[i] == '1')) {
            if (carry_one == true)
                result_str[i] = '0';
            else
                result_str[i] = '1';
        }

        if (n1[i] == '1' && n2[i] == '1') {
            if (carry_one == true) {
                result_str[i] = '1';
            } else {
                result_str[i] = '0';
                carry_one = true;
            }
        }
    }

    result = bin_str_to_int(result_str);
    printf("Resultado = %i (%s)\n", result, result_str);
    return 0;
}