Random word from file #5

hangman.c

@@ -4,7 +4,8 @@
 #include <string.h>
 #include <ctype.h> //tolower
 #include <getopt.h>
-
+#include <time.h>
+#include "prng.h"
 
 int main(int argc, char **argv) {
   
@@ -55,6 +56,7 @@ int main(int argc, char **argv) {
             break;
         }
     }
+    InitializePRNG(time(NULL)); /* Initialize random number generator */
     
     if (startscr) {
         showStartScreen(gs);
@@ -112,12 +114,22 @@ void initGuessWord(game_state *gs, char *filename) {
     int i;
     mvprintw(1, 1, "Please enter your word: ");
     if (strlen(gs->guessWord) == 0) { /* Word can be set by arguments */
+        if (strlen(filename) == 0) {
+            /* Manual input */
             curs_set(1);
             getstr(gs->guessWord);
             curs_set(0);
+        } else {
+            /* Random line from file */
+            readRandomLine(filename, gs->guessWord);
         }
+            
+    }
+
+    /* Make String all lowercase */
     toLowerCase(gs->guessWord);
     gs->wordLength = strlen(gs->guessWord);
+
     for (i = 0; i < gs->wordLength; i++) {
         if (gs->guessWord[i] == ' ') { //Check for spaces if it's a sentence
             gs->currentWord[i] = ' ';
@@ -230,7 +242,8 @@ int checkWin(game_state *gs) {
 void printGameStats(game_state *gs) {
     clear();
     if (gs->moves >= gs->allowedMoves) {
-        mvprintw(gs->centery, gs->centerx - 5, "Game lost.");
+        mvprintw(gs->centery, gs->centerx - 10, "Game lost. Solution:");
+        mvprintw(gs->centery + 1, gs->centerx - (gs->wordLength / 2), gs->guessWord);
     } else {
         char message[100];
         sprintf(message, "Game won! Total guesses: %i", gs->guesses);
@@ -251,3 +264,20 @@ int centerDiff(int coordinate, char *str) {
     int len = strlen(str);
     return coordinate - (len / 2); /* Integer division */
 }
+
+void readRandomLine(char *file, char *result) {
+    long totalLength = 0, rand = 0;
+    FILE *fp = fopen(file, "r");
+    char c;
+
+    while ((c = fgetc(fp)) != EOF) {
+        if (c == '\n') ++totalLength;
+    }
+    
+    rand = getrandom(0, totalLength);
+    fseek(fp, rand, SEEK_SET);
+
+    fgets(result, MAXWORDLENGTH, fp);
+
+    fclose(fp);
+}

hangman.h

@@ -1,5 +1,6 @@
 /* Defined macros */
 #define DEFAULTTRIES 9
+#define MAXWORDLENGTH 100
 
 /* Data structures */
 typedef struct {
@@ -10,9 +11,9 @@ typedef struct {
     int maxx;
     int centery;
     int centerx;
-    char guessWord[100];
+    char guessWord[MAXWORDLENGTH];
     int wordLength;
-    char currentWord[100];
+    char currentWord[MAXWORDLENGTH];
     char wrongCharacters[DEFAULTTRIES];
 } game_state;
 
@@ -38,3 +39,4 @@ void showStartScreen(game_state *gs);
 void startGame(game_state *gs);
 void showHelp(game_state *gs);
 int centerDiff(int coordinate, char *str);
+void readRandomLine(char *file, char *result);

makefile

@@ -7,7 +7,7 @@ CFLAGS  = -Wall -g -D_REENTRANT -DVERSION=\"$(VERSION)\"
 #LDFLAGS = -lm -lpthread `gtk-config --cflags` `gtk-config --libs` -lgthread
 LDFLAGS = -lncurses
 
-OBJ = hangman.o
+OBJ = hangman.o prng.o
 
 all: $(OBJ)
 	$(CC) $(CFLAGS) -o hangman $(OBJ) $(LDFLAGS)

prng.c

@@ -0,0 +1,91 @@
+
+#include "prng.h"
+// Define MT19937 constants (32-bit RNG)
+enum
+{
+    // Assumes W = 32 (omitting this)
+    N = 624,
+    M = 397,
+    R = 31,
+    A = 0x9908B0DF,
+
+    F = 1812433253,
+
+    U = 11,
+    // Assumes D = 0xFFFFFFFF (omitting this)
+
+    S = 7,
+    B = 0x9D2C5680,
+
+    T = 15,
+    C = 0xEFC60000,
+
+    L = 18,
+
+    MASK_LOWER = (1ull << R) - 1,
+    MASK_UPPER = (1ull << R)
+};
+
+static uint32_t  mt[N];
+static uint16_t  index;
+
+// Re-init with a given seed
+void InitializePRNG(const uint32_t  seed)
+{
+    uint32_t  i;
+
+    mt[0] = seed;
+
+    for ( i = 1; i < N; i++ )
+    {
+        mt[i] = (F * (mt[i - 1] ^ (mt[i - 1] >> 30)) + i);
+    }
+
+    index = N;
+}
+
+static void Twist()
+{
+    uint32_t  i, x, xA;
+
+    for ( i = 0; i < N; i++ )
+    {
+        x = (mt[i] & MASK_UPPER) + (mt[(i + 1) % N] & MASK_LOWER);
+
+        xA = x >> 1;
+
+        if ( x & 0x1 )
+            xA ^= A;
+
+        mt[i] = mt[(i + M) % N] ^ xA;
+    }
+
+    index = 0;
+}
+
+// Obtain a 32-bit random number
+uint32_t ExtractU32()
+{
+    uint32_t  y;
+    int       i = index;
+
+    if ( index >= N )
+    {
+        Twist();
+        i = index;
+    }
+
+    y = mt[i];
+    index = i + 1;
+
+    y ^= (mt[i] >> U);
+    y ^= (y << S) & B;
+    y ^= (y << T) & C;
+    y ^= (y >> L);
+
+    return y;
+}
+
+int getrandom(int low, int high) {
+    return ((ExtractU32() % high) + low);
+}

prng.h

@@ -0,0 +1,9 @@
+/**
+ * Pseudo random number generator using the Mersenne Twister algorithm
+ * This code was taken from wikipedia: https://en.wikipedia.org/wiki/Mersenne_Twister
+ */
+#include <stdint.h>
+
+void InitializePRNG(const uint32_t  seed);
+uint32_t ExtractU32();
+int getrandom(int low, int high);