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

void merge(double *a, int sizeA, double *b, int sizeB, double *c);

int main(void) {
    FILE *INA, *INB, *OUT;
    double x, *A, *B, *C;
    int NA = 0, NB = 0, NC, i;

    /* Count numbers in ina.txt */
    INA = fopen("ina.txt", "r");
    if (INA == NULL) {
        printf("File ina.txt not opened\n");
        return -1;
    }
    while (fscanf(INA, "%lf", &x) == 1)
        ++NA;
    fclose(INA);
    if (NA <= 0) {
        printf("File ina.txt empty\n");
        return -1;
    }
    /* Allocate memory for array A */
    A = (double*)malloc(NA * sizeof(A[0]));
    if (A == NULL) {
        printf("Memory not allocated\n");
        return -1;
    }
    /* Read array A from ina.txt */
    INA = fopen("ina.txt", "r");
    if (INA == NULL) {
        printf("File ina.txt not opened\n");
        return -1;
    }
    for (i = 0; i < NA; i++) {
        if (fscanf(INA, "%lf", &A[i]) != 1) {
            printf("Not enough numbers\n");
            return -1;
        }
    }
    fclose(INA);

    /* Count numbers in inb.txt */
    INB = fopen("inb.txt", "r");
    if (INB == NULL) {
        printf("File ina.txt not opened\n");
        return -1;
    }
    while (fscanf(INB, "%lf", &x) == 1)
        ++NB;
    fclose(INB);
    if (NA <= 0) {
        printf("File ina.txt empty\n");
        return -1;
    }
    /* Allocate memory for array A */
    B = (double*)malloc(NB * sizeof(B[0]));
    if (B == NULL) {
        printf("Memory not allocated\n");
        return -1;
    }
    /* Read array A from ina.txt */
    INB = fopen("inb.txt", "r");
    if (INB == NULL) {
        printf("File inb.txt not opened\n");
        return -1;
    }
    for (i = 0; i < NB; i++) {
        if (fscanf(INB, "%lf", &B[i]) != 1) {
            printf("Not enough numbers\n");
            return -1;
        }
    }
    fclose(INB);

    NC = NA + NB;
    C = (double*)malloc(NC * sizeof(C[0]));
    if (C == NULL) {
        free(A);
        free(B);
        printf("Memory not allocated\n");
        return -1;
    }

    /* Create file output.txt */
    OUT = fopen("output.txt", "w");
    if (OUT == NULL) {
        free(A);
        free(B);
        printf("File output.txt not opened\n");
        return -1;
    }

    /* Merge arrays A and B to array C */
    merge(A, NA, B, NB, C);

    /* Output array C to output.txt */
    for (i = 0; i < NC; i++) {
        fprintf(OUT, "%lf ", C[i]);
    }
    fclose(OUT);
    free(A);
    free(B);
    free(C);
    return 0;
}

void merge(double *a, int sizeA, double *b, int sizeB, double *c) {
    int sizeC = sizeA + sizeB;
    int i = 0, j = 0, k;
    for (k = 0; k < sizeC; k++) {
        if ((i < sizeA) && ((j >= sizeB) || (a[i] < b[j]))) {
            c[k] = a[i++];
        } else {
            c[k] = b[j++];
        }
    }
}