parallel

#include<stdio.h>
#include<string.h>
#include<mpi.h>


int main(void){

MPI_Init(NULL,NULL);
int proc_rank;
MPI_Comm_rank(MPI_COMM_WORLD, &proc_rank);
int proc_size;
MPI_Comm_size(MPI_COMM_WORLD, &proc_size);

if (proc_rank == 0) { //Chteniya proizvoditsya v processe 0 i otpravlyaetsya toje s etogo
    int c;
    FILE *file;
    char a[10000];
    int len = 0;
    file = fopen("test.txt", "r"); //Dlya chteniya s faila
    if (file) {
        while ((c = getc(file)) != EOF) // poka not end of file chitaem kajdyi simvol po ocheredi i kladem v massiv
            a[len++] = c;
        fclose(file);
    }
    int left = 0; //nachalo sleduiwego bloka teksta(charovski massiv a[])
    int rem = len % (proc_size-1); //nam nujno podelit' tekst rovno dlya kajdogo processa
    for(int i = 1; i < proc_size; i++){ // vot zdes' uje otpravlyaem kajdyi block i
        int block_size = (len / (proc_size-1)); //dlina dlya tekuwego bloka            [7,7,7,6] rem = 3
    if (rem > 0) { block_size++; rem--; } //nekotorye dliny ne delyatsya rovno kak 27 na 4 processa naprimer i 3 ostavwiesya my toje doljny razdelit' po blokam
    int right = left + block_size - 1; //konec tekuwego bloka

    char temp[block_size]; //copyruem block v a[left,right] na drugoi massiv temp[0,right-left+1]
    for(int j = left; j < right; j++) temp[j-left] = a[j];
    MPI_Send(&block_size, 1, MPI_INT, i, 0, MPI_COMM_WORLD); //snachala otpravlyaem dlinu bloka chtob tam v drugom processe vstretil
        MPI_Send(temp, block_size+1, MPI_CHAR, i, 1, MPI_COMM_WORLD); //teper' uje sam blok
        MPI_Recv(temp,block_size+1, MPI_CHAR, i, 2, MPI_COMM_WORLD, MPI_STATUS_IGNORE); //zdes' uje prinimaem reversed block
        for(int j = left; j < right; j++) a[j] = temp[j-left]; // i stavim obratno na mesto v a[]
    left = right + 1; // uzhe nachalo sleduwego bloka
    }
    FILE *fp = fopen("reversed.txt", "ab");
    if (fp != NULL)
    {
        fputs(data, fp);// Vyvod na file
        fclose(fp);
    }
} else if (proc_rank != 0) {
    int length;
    MPI_Recv(&length, 1 , MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE); //vot tut process i prinimaet dlinu bloka kotoryi vot vot pridet
    char str[length];
    MPI_Recv(str,length+1, MPI_CHAR, 0, 1, MPI_COMM_WORLD, MPI_STATUS_IGNORE); // i vidite my doljny uzhe vstretit' s pomow'u dliny(vtoroi parameter)
    int i = 0;
    int j = length-1; //Tut proishodit reverse
    while (i < j) {
        temp = str[i];
        str[i] = str[j];
        str[j] = temp;
        i++;
        j--;
    }
    MPI_Send(str, length+1, MPI_CHAR, 0, 2, MPI_COMM_WORLD); //i otpravlyaetsya obratno
}
}