{"id":145793,"date":"2025-07-11T14:44:48","date_gmt":"2025-07-11T09:14:48","guid":{"rendered":"https:\/\/data-flair.training\/blogs\/?p=145793"},"modified":"2025-07-11T14:44:48","modified_gmt":"2025-07-11T09:14:48","slug":"traffic-light-simulation-in-data-structures","status":"publish","type":"post","link":"https:\/\/data-flair.training\/blogs\/traffic-light-simulation-in-data-structures\/","title":{"rendered":"DSA Project &#8211; Traffic Light Simulation"},"content":{"rendered":"<h3>Program 1<\/h3>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">\/\/ Project: Traffic Light Simulation Using Queue Linked List \r\n\/\/----------------------------------------------------------\r\n\/\/ Features:\r\n\/\/ Add vehicles to queue (simulating arrival)\r\n\/\/ Process vehicles when the signal turns green\r\n\/\/ Show vehicles in the queue\r\n\/\/ Count waiting vehicles\r\n\/\/ Clear All Vehicles (Emergency Clear Signal)\r\n\/\/Search for a Vehicle by Number\r\n\/\/Display First and Last Vehicle in Queue\r\n\/\/Log of Passed Vehicles\r\n\r\n#include &lt;stdio.h&gt;\r\n#include &lt;stdlib.h&gt;\r\n#include &lt;string.h&gt;\r\n\r\n#define SIZE 100\r\n\r\ntypedef struct Vehicle   \/\/ Node \r\n{\r\n    char number[20];  \r\n    struct Vehicle* next;\r\n} Vehicle;\r\n\r\nVehicle* front = NULL;\r\nVehicle* rear = NULL;\r\nVehicle* passedLog = NULL;  \/\/ Passed vehicle log\r\n\r\n\/\/ Enqueue vehicle\r\nvoid arriveVehicle(const char* number) \r\n{\r\n    Vehicle* temp = (Vehicle*)malloc(sizeof(Vehicle));\r\n    strcpy(temp-&gt;number, number);\r\n    temp-&gt;next = NULL;\r\n\r\n    if (rear == NULL) \r\n    {\r\n        front = rear = temp;\r\n    } else \r\n    {\r\n        rear-&gt;next = temp;\r\n        rear = temp;\r\n    }\r\n    printf(\"\\n Vehicle %s arrived at the signal.\\n\", number);\r\n}\r\n\r\n\/\/ Add vehicle to log\r\nvoid logPassedVehicle(const char* number) \r\n{\r\n    Vehicle* temp = (Vehicle*)malloc(sizeof(Vehicle));\r\n    strcpy(temp-&gt;number, number);\r\n    temp-&gt;next = NULL;\r\n\r\n    if (passedLog == NULL) \r\n    {\r\n        passedLog = temp;\r\n    } else \r\n    {\r\n        Vehicle* ptr = passedLog;\r\n        while (ptr-&gt;next != NULL)\r\n            ptr = ptr-&gt;next;\r\n        ptr-&gt;next = temp;\r\n    }\r\n}\r\n\r\n\/\/ Dequeue vehicle\r\nvoid passVehicle()\r\n {\r\n    if (front == NULL) \r\n    {\r\n        printf(\"\\n No vehicles waiting at the signal.\\n\");\r\n        return;\r\n    }\r\n\r\n    Vehicle* temp = front;\r\n    printf(\"\\n Vehicle %s passed the signal.\\n\", temp-&gt;number);\r\n    logPassedVehicle(temp-&gt;number);\r\n    front = front-&gt;next;\r\n\r\n    if (front == NULL)\r\n       front=rear = NULL;\r\n\r\n    free(temp);\r\n}\r\n\r\n\/\/ View all vehicles waiting\r\nvoid displayQueue() \r\n{\r\n    if (front == NULL) \r\n    {\r\n        printf(\"\\nNo vehicles in the queue.\\n\");\r\n        return;\r\n    }\r\n\r\n    printf(\"\\n Vehicles at signal:\\n\");\r\n    Vehicle* temp = front;\r\n    while (temp != NULL) \r\n    {\r\n        printf(\"  -&gt; %s\\n\", temp-&gt;number);\r\n        temp = temp-&gt;next;\r\n    }\r\n}\r\n\r\n\/\/ Count waiting vehicles\r\nvoid countQueue() \r\n{\r\n    int count = 0;\r\n    Vehicle* temp = front;\r\n    while (temp != NULL) \r\n    {\r\n        count++;\r\n        temp = temp-&gt;next;\r\n    }\r\n    printf(\"\\nTotal vehicles waiting: %d\\n\", count);\r\n}\r\n\r\n\/\/ Emergency clear\r\nvoid clearQueue() \r\n{\r\n    while (front != NULL) \r\n    {\r\n        Vehicle* temp = front;\r\n        front = front-&gt;next;\r\n        free(temp);\r\n    }\r\n    rear = NULL;\r\n    printf(\"\\nAll vehicles cleared from the signal!\\n\");\r\n}\r\n\r\n\/\/ Search for a vehicle\r\nvoid searchVehicle(const char* number)\r\n {\r\n\r\n    Vehicle* temp = front;\r\n      while (temp != NULL) \r\n     {\r\n        if (strcmp(temp-&gt;number, number) == 0) \r\n        {\r\n            printf(\"\\n Vehicle %s is currently in the queue.\\n\", number);\r\n            return;\r\n        }\r\n        temp = temp-&gt;next;\r\n     }\r\n     printf(\"\\n Vehicle %s not found in queue.\\n\", number);\r\n}\r\n\r\n\/\/ Show first and last vehicle\r\nvoid showFirstAndLast() \r\n{\r\n    if (front == NULL) {\r\n        printf(\"\\n No vehicles in the queue.\\n\");\r\n        return;\r\n    }\r\n    printf(\"\\nFirst Vehicle: %s\\n\", front-&gt;number);\r\n    printf(\"Last Vehicle: %s\\n\", rear-&gt;number);\r\n}\r\n\r\n\/\/ Show passed vehicle log\r\nvoid showPassedLog() \r\n{\r\n    if (passedLog == NULL) \r\n    {\r\n        printf(\"\\nNo vehicles have passed the signal yet.\\n\");\r\n        return;\r\n    }\r\n    printf(\"\\nPassed Vehicles Log:\\n\");\r\n    Vehicle* temp = passedLog;\r\n    while (temp != NULL) \r\n    {\r\n        printf(\"  -&gt; %s\\n\", temp-&gt;number);\r\n        temp = temp-&gt;next;\r\n    }\r\n}\r\n\r\n\/\/ Menu\r\nvoid menu() {\r\n    int choice;\r\n    char number[20];\r\n\r\n    do {\r\n        printf(\"\\n========== Traffic Light Simulation ==========\");\r\n        printf(\"\\n1. Vehicle Arrives\");\r\n        printf(\"\\n2. Signal Turns Green (Vehicle Passes)\");\r\n        printf(\"\\n3. Show Vehicles in Queue\");\r\n        printf(\"\\n4. Count Waiting Vehicles\");\r\n        printf(\"\\n5. Emergency Clear All Vehicles\");\r\n        printf(\"\\n6. Search Vehicle by Number\");\r\n        printf(\"\\n7. Show First and Last Vehicle\");\r\n        printf(\"\\n8. Show Passed Vehicle Log\");\r\n        printf(\"\\n9. Exit\\n\");\r\n       printf(\"\\n=====================================\\n\");  \r\n        printf(\"Choose an option: \");\r\n        scanf(\"%d\", &amp;choice);\r\n        getchar(); \/\/ clear newline\r\n\r\n        switch (choice)\r\n         {\r\n            case 1:\r\n                printf(\"Enter vehicle number: \");\r\n                fgets(number, sizeof(number), stdin);\r\n                number[strcspn(number, \"\\n\")] = 0;\r\n                arriveVehicle(number);\r\n                break;\r\n            case 2:\r\n                passVehicle();\r\n                break;\r\n            case 3:\r\n                displayQueue();\r\n                break;\r\n            case 4:\r\n                countQueue();\r\n                break;\r\n            case 5:\r\n                clearQueue();\r\n                break;\r\n            case 6:\r\n              if(front==NULL) \r\n               printf(\"No vehicle in queue........\");\r\n               else\r\n               {\r\n                 printf(\"Enter vehicle number to search: \");\r\n                 fgets(number, sizeof(number), stdin);\r\n                 number[strcspn(number, \"\\n\")] = 0;\r\n                 searchVehicle(number);\r\n               }  \r\n                break;\r\n            case 7:\r\n                showFirstAndLast();\r\n                break;\r\n            case 8:\r\n                showPassedLog();\r\n                break;\r\n            case 9:\r\n                printf(\"\\nExiting simulation. Goodbye!\\n\");\r\n                break;\r\n            default:\r\n                printf(\"\\nInvalid option. Try again.\\n\");\r\n        }\r\n    } while (choice != 9);\r\n}\r\n\r\nint main() {\r\n    menu();\r\n    return 0;\r\n}<\/pre>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Program 1 \/\/ Project: Traffic Light Simulation Using Queue Linked List \/\/&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;&#8212;- \/\/ Features: \/\/ Add vehicles to queue (simulating arrival) \/\/ Process vehicles when the signal turns green \/\/ Show vehicles in the&#46;&#46;&#46;<\/p>\n","protected":false},"author":581,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24020],"tags":[24331,34844,32874,34874,34875,34876,34879,32249,34813,34877,34866,34878],"class_list":["post-145793","post","type-post","status-publish","format-standard","hentry","category-data-structure-tutorials","tag-data-structures","tag-dsa","tag-dsa-c","tag-dsa-practical","tag-dsa-program","tag-dsa-project","tag-dsa-traffic-light-simulation-project","tag-dsa-using-c","tag-traffic-light-simulation","tag-traffic-light-simulation-in-data-structures","tag-traffic-light-simulation-project","tag-traffic-light-simulation-project-in-dsa"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.4 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>DSA Project - Traffic Light Simulation - DataFlair<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/data-flair.training\/blogs\/traffic-light-simulation-in-data-structures\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"DSA Project - Traffic Light Simulation - DataFlair\" \/>\n<meta property=\"og:description\" content=\"Program 1 \/\/ Project: Traffic Light Simulation Using Queue Linked List \/\/---------------------------------------------------------- \/\/ Features: \/\/ Add vehicles to queue (simulating arrival) \/\/ Process vehicles when the signal turns green \/\/ Show vehicles in the&#046;&#046;&#046;\" \/>\n<meta property=\"og:url\" content=\"https:\/\/data-flair.training\/blogs\/traffic-light-simulation-in-data-structures\/\" \/>\n<meta property=\"og:site_name\" content=\"DataFlair\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/DataFlairWS\/\" \/>\n<meta property=\"article:published_time\" content=\"2025-07-11T09:14:48+00:00\" \/>\n<meta name=\"author\" content=\"DataFlair Team\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@DataFlairWS\" \/>\n<meta name=\"twitter:site\" content=\"@DataFlairWS\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"DataFlair Team\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"DSA Project - Traffic Light Simulation - DataFlair","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/data-flair.training\/blogs\/traffic-light-simulation-in-data-structures\/","og_locale":"en_US","og_type":"article","og_title":"DSA Project - Traffic Light Simulation - DataFlair","og_description":"Program 1 \/\/ Project: Traffic Light Simulation Using Queue Linked List \/\/---------------------------------------------------------- \/\/ Features: \/\/ Add vehicles to queue (simulating arrival) \/\/ Process vehicles when the signal turns green \/\/ Show vehicles in the&#46;&#46;&#46;","og_url":"https:\/\/data-flair.training\/blogs\/traffic-light-simulation-in-data-structures\/","og_site_name":"DataFlair","article_publisher":"https:\/\/www.facebook.com\/DataFlairWS\/","article_published_time":"2025-07-11T09:14:48+00:00","author":"DataFlair Team","twitter_card":"summary_large_image","twitter_creator":"@DataFlairWS","twitter_site":"@DataFlairWS","twitter_misc":{"Written by":"DataFlair Team","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/data-flair.training\/blogs\/traffic-light-simulation-in-data-structures\/#article","isPartOf":{"@id":"https:\/\/data-flair.training\/blogs\/traffic-light-simulation-in-data-structures\/"},"author":{"name":"DataFlair Team","@id":"https:\/\/data-flair.training\/blogs\/#\/schema\/person\/c187795dc82ab948373cca526df7c445"},"headline":"DSA Project &#8211; 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