#include <stdio.h>
   #define MAXLINE 1000 /* maximum input line length */

   int getline(char line[], int max)
   int strindex(char source[], char searchfor[]);

   char pattern[] = "ould";   /* pattern to search for */

   /* find all lines matching pattern */
   main()
   {
       char line[MAXLINE];
       int found = 0;

       while (getline(line, MAXLINE) > 0)
           if (strindex(line, pattern) >= 0) {
               printf("%s", line);
               found++;
           }
       return found;
   }

   /* getline:  get line into s, return length */
   int getline(char s[], int lim)
   {
       int c, i;

       i = 0;
       while (--lim > 0 && (c=getchar()) != EOF && c != '\n')
           s[i++] = c;
       if (c == '\n')
           s[i++] = c;
       s[i] = '\0';
       return i;
   }

   /* strindex:  return index of t in s, -1 if none */
   int strindex(char s[], char t[])
   {
       int i, j, k;

       for (i = 0; s[i] != '\0'; i++) {
           for (j=i, k=0; t[k]!='\0' && s[j]==t[k]; j++, k++)
               ;
           if (k > 0 && t[k] == '\0')
               return i;
       }
       return -1;
   }

   #include <ctype.h>

   /* atof:  convert string s to double */
   double atof(char s[])
   {
       double val, power;
       int i, sign;

       for (i = 0; isspace(s[i]); i++)  /* skip white space */
           ;
       sign = (s[i] == '-') ? -1 : 1;
       if (s[i] == '+' || s[i] == '-')
           i++;
       for (val = 0.0; isdigit(s[i]); i++)
           val = 10.0 * val + (s[i] - '0');
       if (s[i] == '.')
           i++;
       for (power = 1.0; isdigit(s[i]); i++) {
           val = 10.0 * val + (s[i] - '0');
           power *= 10;
       }
       return sign * val / power;
   }

   #include <stdio.h>

   #define MAXLINE 100

   /* rudimentary calculator */
   main()
   {
       double sum, atof(char []);
       char line[MAXLINE];
       int getline(char line[], int max);

       sum = 0;
       while (getline(line, MAXLINE) > 0)
           printf("\t%g\n", sum += atof(line));
       return 0;
   }

   /* atoi:  convert string s to integer using atof */
   int atoi(char s[])
   {
       double atof(char s[]);

       return (int) atof(s);
   }

   #include <stdio.h>
   #include <stdlib.h>  /* for  atof() */

   #define MAXOP   100  /* max size of operand or operator */
   #define NUMBER  '0'  /* signal that a number was found */

   int getop(char []);
   void push(double);
   double pop(void);

   /* reverse Polish calculator */
   main()
   {
       int type;
       double op2;
       char s[MAXOP];

       while ((type = getop(s)) != EOF) {
           switch (type) {
           case NUMBER:
               push(atof(s));
               break;
           case '+':
               push(pop() + pop());
               break;
           case '*':
               push(pop() * pop());
               break;
           case '-':
               op2 = pop();
               push(pop() - op2);
               break;
           case '/':
               op2 = pop();
               if (op2 != 0.0)
                   push(pop() / op2);
               else
                   printf("error: zero divisor\n");
               break;
           case '\n':
               printf("\t%.8g\n", pop());
               break;
           default:
               printf("error: unknown command %s\n", s);
               break;
           }
       }
       return 0;
   }

   #define MAXVAL  100  /* maximum depth of val stack */

   int sp = 0;          /* next free stack position */
   double val[MAXVAL];  /* value stack */

   /* push:  push f onto value stack */
   void push(double f)
   {
       if (sp < MAXVAL)
           val[sp++] = f;
       else
           printf("error: stack full, can't push %g\n", f);
   }

   /* pop:  pop and return top value from stack */
   double pop(void)
   {
       if (sp > 0)
           return val[--sp];
       else {
           printf("error: stack empty\n");
           return 0.0;
       }
   }

   #include <ctype.h>

   int getch(void);
   void ungetch(int);

   /* getop:  get next character or numeric operand */
   int getop(char s[])
   {
       int i, c;

       while ((s[0] = c = getch()) == ' ' || c == '\t')
           ;
       s[1] = '\0';
       if (!isdigit(c) && c != '.')
           return c;      /* not a number */
       i = 0;
       if (isdigit(c))    /* collect integer part */
           while (isdigit(s[++i] = c = getch()))
              ;
       if (c == '.')      /* collect fraction part */
           while (isdigit(s[++i] = c = getch()))
              ;
       s[i] = '\0';
       if (c != EOF)
           ungetch(c);
       return NUMBER;
   }

   #define BUFSIZE 100

   char buf[BUFSIZE];    /* buffer for ungetch */
   int bufp = 0;         /* next free position in buf */

   int getch(void)  /* get a (possibly pushed-back) character */
   {
       return (bufp > 0) ? buf[--bufp] : getchar();
   }

   void ungetch(int c)   /* push character back on input */
   {
       if (bufp >= BUFSIZE)
           printf("ungetch: too many characters\n");
       else
           buf[bufp++] = c;
   }

   #include <stdio.h>

   /* printd:  print n in decimal */
   void printd(int n)
   {
       if (n < 0) {
           putchar('-');
           n = -n;
       }
       if (n / 10)
           printd(n / 10);
       putchar(n % 10 + '0');
   }

   /* qsort:  sort v[left]...v[right] into increasing order */
   void qsort(int v[], int left, int right)
   {
       int i, last;
       void swap(int v[], int i, int j);

       if (left >= right) /* do nothing if array contains */
           return;        /* fewer than two elements */
       swap(v, left, (left + right)/2); /* move partition elem */
       last = left;                     /* to v[0] */
       for (i = left + 1; i <= right; i++)  /* partition */
           if (v[i] < v[left])
               swap(v, ++last, i);
       swap(v, left, last);            /* restore partition  elem */
       qsort(v, left, last-1);
       qsort(v, last+1, right);
   }

   /* swap:  interchange v[i] and v[j] */
   void swap(int v[], int i, int j)
   {
       int temp;

       temp = v[i];
       v[i] = v[j];
       v[j] = temp;
   }