#include <stdio.h>

#define STRING "This is a string"

int main()
{
    char *s1=STRING;
    char *s2=STRING;
    char t1[]=STRING;
    char t2[]=STRING;
    printf("%p %p %p %p\n",s1,s2,t1,t2);
    printf("%ld %ld\n",sizeof(s1),sizeof(t1));
}




#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
void myStrcat(char *a, char *b)
{
    int m = strlen(a);
    int n = strlen(b);
    int i;
    for (i = 0; i <= n; i++)
       a[m+i]  = b[i];
}
 
int main()
{
    char *str1 = "Geeks ";
    char *str2 = "Quiz";
    myStrcat(str1, str2);
    printf("%s ", str1);
    return 0;
}




# include <stdio.h>
 
int main()
{
   char str1[] = "GeeksQuiz";
   char str2[] = {'G', 'e', 'e', 'k', 's', 'Q', 'u', 'i', 'z'};
   int n1 = sizeof(str1)/sizeof(str1[0]);
   int n2 = sizeof(str2)/sizeof(str2[0]);
   printf("n1 = %d, n2 = %d", n1, n2);
   return 0;
}




#include <stdio.h>
int fun(char *str1)
{
  char *str2 = str1;
  while(*++str1);
  return (str1-str2);
}
 
int main()
{
  char *str = "GeeksQuiz";
  printf("%d", fun(str));
  return 0;
}




#include <stdio.h>
#include <string.h>

int main()
{
    char p[20]; 
    char *s = "string"; 
    int length = strlen(s); 
    int i; 
    for (i = 0; i < length; i++) 
        p[i] = s[length-i]; 
    printf("%s", p);
}




#include <stdio.h>
#include <string.h>

int main()
{
    char p[20]; 
    char *s = "string"; 
    int length = strlen(s); 
    int i; 
    for (i = 1; i <= length; i++) 
        p[i-1] = s[length-i]; 
    printf("%s", p);
}




#include <stdio.h>
int count() {
   static int count = 0;
   return ++count;
}
int main() {
  printf("%d ", count());
  printf("%d ", count());
  printf("%d ", count());
  return 0;
}




#include <stdio.h>
int count() {
   int count = 0;
   return ++count;
}
int main() {
  printf("%d ", count());
  printf("%d ", count());
  printf("%d ", count());
  return 0;
}




#include <stdio.h>
int count = 0;

int count1() {
   return ++count;
}

int count2() {
   return ++count;
}

int main() {
  printf("%d ", count1());
  printf("%d ", count2());
  printf("%d ", count1());
  return 0;
}




#include <stdio.h>

int count1() {
   static int count=0;
   return ++count;
}

int count2() {
   static int count=0;
   return ++count;
}

int main() {
  printf("%d ", count1());
  printf("%d ", count2());
  printf("%d ", count1());
  return 0;
}




#include <stdio.h>
int fun()
{
    static int i=5;
    if (--i){
        printf("%d ",i);
        fun();
    }
    return 0;
}

int main()
{
    fun();
    return 0;
}




//%args:file.txt fileout.txt

#include <stdio.h>
#include <stdlib.h>

void main(int argc, char *argv[])
{
    int c;
    FILE *from, *to;

    /*
     * Check arguments.
     */
    if (argc != 3) {
        fprintf(stderr, "Usage: %s from-file to-file\n", *argv);
        exit(1);
    }

    /*
     * Open the from-file in read mode
     */
    if ((from = fopen(argv[1], "r")) == NULL) {
        perror(argv[1]);
        exit(1);
    }

    /*
     * Open the to-file in write mode.  
     * If to-file does not exist, fopen will create it
     * If to-file exists, it will be truncated
     */
    if ((to = fopen(argv[2], "w")) == NULL) {
        perror(argv[2]);
        exit(1);
    }

    printf("Reading %s\n",argv[1]);
    printf("Writing %s\n",argv[2]);
    /*
     * Now read characters from from-file until we
     * hit end-of-file, and put them onto to-file.
     */

    while ((c = getc(from)) != EOF)
        putc(c, to);

    /*
     * Close both files.
     */
    fclose(from);
    fclose(to);
    printf("Done\n");
    exit(0);
}




//%args:file.txt fileout.txt

#include <stdio.h>
#include <stdlib.h>

int main(argc, argv)
int argc;
char *argv[];
{
    FILE *from, *to;
    char line[BUFSIZ];
    /*
     * Check our arguments.
     */
    if (argc != 3) {
        fprintf(stderr, "Usage: %s from-file to-file\n", *argv);
        exit(1);
    }
    /*
     * Open the from-file in read mode
     */
    if ((from = fopen(argv[1], "r")) == NULL) {
        perror(argv[1]);
        exit(1);
    }
    /*
     * Open the to-file in write mode.
     */
    if ((to = fopen(argv[2], "w")) == NULL) {
        perror(argv[2]);
        exit(1);
    }
    printf("Reading %s\n",argv[1]);
    printf("Writing %s\n",argv[2]);
    
    /*
     * Now read a line at a time from the from-file,
     * and write it to the to-file.
     */
    while (fgets(line, BUFSIZ, from) != NULL)
        fputs(line, to);
    /*
     * Close the files.
     */
    fclose(from);
    fclose(to);
    printf("Done\n");
    exit(0);
}





//%args:file.txt fileout.txt

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv)
{
    int n;
    FILE *from, *to;
    char buf[BUFSIZ];

    /*
     * Check our arguments.
     */
    if (argc != 3) {
        fprintf(stderr, "Usage: %s from-file to-file\n", *argv);
        exit(1);
    }

    /*
     * Open the from-file in read mode
     */
    if ((from = fopen(argv[1], "r")) == NULL) {
        perror(argv[1]);
        exit(1);
    }

    /*
     * Open the to-file in append mode
     */
    if ((to = fopen(argv[2], "a")) == NULL) {
        perror(argv[2]);
        exit(1);
    }

    printf("Reading %s\n",argv[1]);
    printf("Writing %s\n",argv[2]);
    /*
     * Note that we only write the number of characters fread 
     * read in, rather than always writing BUFSIZ characters.
     */
    while ((n = fread(buf, sizeof(char), BUFSIZ, from)) > 0)
        fwrite(buf, sizeof(char), n, to);

    /*
     * Now close the files.
     */
    fclose(from);
    fclose(to);
    printf("Done\n");
    exit(0);
}





//%args:file.txt

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define LINELEN 132
#define NUMLINES 10

void print(char *p[], int n)
{
    int i=0;
    for (i=0; i<n; i++) {
        printf("<%s>\n",p[i]);
    }
}

void sort(char *p[], int n)
{
    int done=0;

    while (!done) {
        int item=n-1;
        done=1;

        while (item>0) {
            if (strcmp(p[item],p[item-1])<0) {
                char *temp=p[item];
                p[item]=p[item-1];
                p[item-1]=temp;
                done=0;
            }
            item -=1;
        }
    }
}

void main(int argc, char *argv[])
{
    FILE *fp=NULL;
    int nlines=NUMLINES;
    int i=0;
    char **array=NULL;
    char line[LINELEN];

    printf("Reading %s\n",argv[1]);
    if (!(fp=fopen(argv[1],"r"))) {
        perror("fopen");
        exit(1);
    }
  
    array=malloc(nlines*sizeof(*array));
    if (!array) {
        perror("malloc");
        exit(1);
    }

    i=0;
    while (fgets(line,sizeof(line),fp)) {
        int l=strlen(line);

        array[i]=malloc(l);
        if (!array[i]) {
            perror("malloc");
            exit(1);
        }
    
        strncpy(array[i],line,l-1);
        array[i][l-1]='\0';

        i +=1;

        if (i>=nlines) {
            nlines=nlines*2;
            array=realloc(array,nlines*sizeof(*array));

            if (!array) {
                perror("malloc");
                exit(1);
            }
        }
    }
    print(array,i);
    printf("**** SORTING ******\n");
    sort(array,i);
    print(array,i);
    printf("Exiting.\n");
}