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  1. #include<stdio.h>
  2.  
  3. #include<math.h>
  4.  
  5. #include<string.h>
  6.  
  7. #include<ctype.h>
  8.  
  9. #include<stdlib.h>
  10.  
  11. int n, m = 0, p, i = 0, j = 0;
  12. char a[10][10], f[10];
  13. void follow(char c);
  14. void first(char c);
  15. int main() {
  16.   int i, z;
  17.   char c, ch;
  18.   printf("Enter the no of productions : \n");
  19.   scanf("%d", & n);
  20.   printf("Enter the productions:\n");
  21.   for (i = 0; i < n; i++)
  22.     scanf("%s%c", a[i], & ch);
  23.   do {
  24.     m = 0;
  25.     printf("Enter a variable whose fisrt & follow is to be found:");
  26.  
  27.     scanf("%c", & c);
  28.     first(c);
  29.     printf("First(%c)={", c);
  30.     for (i = 0; i < m; i++)
  31.       printf("%c", f[i]);
  32.     printf("}\n");
  33.     strcpy(f, " ");
  34.     m = 0;
  35.     follow(c);
  36.     printf("Follow(%c)={", c);
  37.     for (i = 0; i < m; i++)
  38.       printf("%c", f[i]);
  39.     printf("}\n");
  40.     printf("Want to continue or not(1/0) ? ");
  41.     scanf("%d%c", & z, & ch);
  42.   }
  43.   while (z == 1);
  44.   return (0);
  45. }
  46. void first(char c) {
  47.   int k;
  48.   if (!isupper(c))
  49.     f[m++] = c;
  50.   for (k = 0; k < n; k++) {
  51.     if (a[k][0] == c) {
  52.       if (a[k][2] == '$')
  53.         follow(a[k][0]);
  54.       else if (islower(a[k][2]))
  55.         f[m++] = a[k][2];
  56.       else
  57.         first(a[k][2]);
  58.  
  59.     }
  60.   }
  61. }
  62. void follow(char c) {
  63.   if (a[0][0] == c)
  64.     f[m++] = '$';
  65.   for (i = 0; i < n; i++) {
  66.     for (j = 2; j < strlen(a[i]); j++) {
  67.       if (a[i][j] == c) {
  68.         if (a[i][j + 1] != '\0')
  69.           first(a[i][j + 1]);
  70.         if (a[i][j + 1] == '\0' && c != a[i][0])
  71.           follow(a[i][0]);
  72.  
  73.       }
  74.     }
  75.   }
  76. }
Success #stdin #stdout 0.01s 5284KB
comments (?)
stdin
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Standard input is empty
stdout
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Enter the no of productions : 
Enter the productions:
Enter a variable whose fisrt & follow is to be found:First()={}
Follow()={$}
Want to continue or not(1/0) ?
https://ideone.com/qyy1sH
language:
C++ (gcc 8.3)
created:
3 days ago
visibility:
public

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