operating-system/problem-17 at main · gowthamch54/operating-system · GitHub

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

#define MAX_PROCESSES 5
#define MAX_RESOURCES 3

int available[MAX_RESOURCES];
int max[MAX_PROCESSES][MAX_RESOURCES];
int allocation[MAX_PROCESSES][MAX_RESOURCES];
int need[MAX_PROCESSES][MAX_RESOURCES];

bool isSafeState(int processes, int resources) {
    bool finish[MAX_PROCESSES] = {0};
    int work[MAX_RESOURCES];
    for (int i = 0; i < resources; i++) {
        work[i] = available[i];
    }

    while (true) {
        bool found = false;
        for (int p = 0; p < processes; p++) {
            if (!finish[p]) {
                bool canAllocate = true;
                for (int r = 0; r < resources; r++) {
                    if (need[p][r] > work[r]) {
                        canAllocate = false;
                        break;
                    }
                }
                if (canAllocate) {
                    for (int r = 0; r < resources; r++) {
                        work[r] += allocation[p][r];
                    }
                    finish[p] = true;
                    found = true;
                }
            }
        }
        if (!found) {
            break;
        }
    }

    for (int p = 0; p < processes; p++) {
        if (!finish[p]) {
            return false;
        }
    }
    return true;
}

void requestResources(int p, int resources) {
    printf("Enter the request for process %d:\n", p);
    int request[MAX_RESOURCES];
    for (int i = 0; i < resources; i++) {
        scanf("%d", &request[i]);
    }

    bool validRequest = true;
    for (int i = 0; i < resources; i++) {
        if (request[i] > need[p][i]) {
            validRequest = false;
            break;
        }
    }

    if (validRequest) {
        for (int i = 0; i < resources; i++) {
            if (request[i] > available[i]) {
                validRequest = false;
                break;
            }
        }
    }

    if (validRequest) {
        for (int i = 0; i < resources; i++) {
            available[i] -= request[i];
            allocation[p][i] += request[i];
            need[p][i] -= request[i];
        }

        if (isSafeState(MAX_PROCESSES, resources)) {
            printf("Request can be granted.\n");
        } else {
            for (int i = 0; i < resources; i++) {
                available[i] += request[i];
                allocation[p][i] -= request[i];
                need[p][i] += request[i];
            }
            printf("Request cannot be granted as it leads to unsafe state.\n");
        }
    } else {
        printf("Request cannot be granted.\n");
    }
}

int main() {
    int processes = MAX_PROCESSES;
    int resources = MAX_RESOURCES;

    printf("Enter the available resources:\n");
    for (int i = 0; i < resources; i++) {
        scanf("%d", &available[i]);
    }

    printf("Enter the maximum resource matrix:\n");
    for (int p = 0; p < processes; p++) {
        for (int r = 0; r < resources; r++) {
            scanf("%d", &max[p][r]);
            need[p][r] = max[p][r];
        }
    }

    printf("Enter the allocation matrix:\n");
    for (int p = 0; p < processes; p++) {
        for (int r = 0; r < resources; r++) {
            scanf("%d", &allocation[p][r]);
            need[p][r] -= allocation[p][r];
        }
    }

    int processNumber;
    printf("Enter the process number to make a request: ");
    scanf("%d", &processNumber);

    requestResources(processNumber, resources);

    return 0;
}