C programming Basic 1

Basic IO:

#include <stdio.h>

#include <stdlib.h>

int main()

{

   char password[15];

   printf("Enter your password:");

   fgets(password, 15, stdin);

 //  scanf("%s", password);

   printf("The password is :");

   puts(password);

    return 0;

}

Random operator:
#include <stdio.h>
#include <stdlib.h>
int main()

{

    int r;

    srand((unsigned)time(NULL));

    r = rand();

    printf("%d is a random number.\n",r);

    return 0;

}

Do …. While:

#include <stdio.h>

#include <stdlib.h>

int main()

{

    char a, b;

    puts("Enter letter: ");

    scanf("%c", &b);

    a = 'a';

    do{

        putchar(a);

        if(a==b) break;

        a++;

    } while(a!='z'+1);

    return 0;

}

Work with char:

#include <stdio.h>

#include <stdlib.h>

#include <ctype.h>

int main()

{

    int ch;

    do{

        ch=getchar();

        ch = toupper(ch);

        putchar(ch);

    } while (ch!='\n');

    return 0;

}

Working with char:

#include <stdio.h>

#include <stdlib.h>

#include <ctype.h>

int main()

{

    int ch;

    char st[100];

    int len;

    fgets(st, 100, stdin);

    len = strlen(st);

    printf("%d", len);

    return 0;

}

Working with array:

#include <stdio.h>

#include <stdlib.h>

#include <ctype.h>

int main()

{

    char first[] = "I would like to go USA";

    int n=0;

    while(first[n]!='\0')

    {

        putchar(first[n]);

        n++;

    }

    return 0;

}
Get value press enter:

#include <stdio.h>
int main ( void ){
    int a[100], i=0;
    int j;
  char again;
  while (again != '\n') {
    scanf("%d", &a[i++]);
    again=getchar();
  }
for(j = 0; j<i; j++) printf("%d ", a[j]);
  return 0;
}
Struct Example:
#include <stdio.h>

int main ( void ){
    struct date{
        int year;
        int month;
        int day;
    };
    struct record {
        char name[32];
        struct date birthday;
    };

    struct record president;
    strcpy(president.name,"Brad Pit");
    president.birthday.year = 1991;
    president.birthday.month = 6;
    president.birthday.day = 1;
    printf("My friend %s was born on %d/%d/%d\n", president.name, president.birthday.year,
           president.birthday.month, president.birthday.day);
  return 0;
}
Time:
#include <stdio.h>
#include <time.h>
int main ( void ){

    time_t now;
    struct tm *right_now;

    time(&now);
    right_now=localtime(&now);
    printf("Today is %d/%d at %d:%d\n", right_now->tm_mon+1,
            right_now->tm_mday, right_now->tm_hour, right_now->tm_min);
  return 0;

}

Pointer and Array:
example 1: #include <stdio.h>
#include <time.h>
int main ( void ){
    int array[]={11, 12, 13, 14};
    int x;
    int *aptr;
    aptr = array;
    for(x = 0; x<4; x++)
        printf("Element %d: %d\n", x+1, *aptr++);
    aptr = array;
    *(aptr +2) = 0;
    for(x = 0; x<4; x++)
        printf("Element %d: %d\n", x+1, array[x]);
  return 0;
}
example 2:
#include <stdio.h>
#include <time.h>
int main ( void ){
    char *string="I'm just a normal string.\n";
    int x =0;
    while(*string)
    {
        putchar(*string++);
    }
  return 0;
}
Pointer Function:
example 1:

#include <stdio.h>

#include <time.h>

void minus10(int *v){

    *v = *v - 10;

}

int main ( void ){

    int v = 100;

    printf("Value is %d\n", v);

    minus10(&v);

    printf("Value is %d\n", v);

  return 0;

}

example 2:

#include <stdio.h>

#include <string.h>

char *longer(char *s1){

  while(*s1){

    *s1 = toupper(*s1);

    *s1++;

  }

}

int main ( void ){

    char string[64];

    printf("Type some text:");

    fgets(string, 64, stdin);

    printf("You typed:\n%s\n", string);

    longer(string);

    printf("If you were shouting, you'd typed: \n%s\n", string);

  return 0;

}

example 3:
#include <stdio.h>
#include <string.h>
char *encrypt(char *input){
    static char output[64];
    int x=0;
    while(*input){
        if(isalpha(*input))
            output[x]=*input+1;
        else output[x]=*input;
        x++;
        input++;
    }
    return output;
}
int main ( void ){
    char *instructions = "Deliver the package to Berlin";
    printf("Here are your secret instructions:\n%s\n",encrypt(instructions));
  return 0;
}

Linked List Example:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct stats{
    int account;
    float balance;
    struct stats *next;
};
void fill_structure(struct stats *s);
struct stats *create(void);

int main ( void ){
    struct stats *first;
    struct stats *current;
    struct stats *new;
    int x;
    first = create();
    current = first;
    for(x = 0; x<5; x++){
        if(x==0){
            first=create();
            current=first;
        }
        else {
            new = create();
            current->next = new;
            current = new;
        }
        fill_structure(current);
    }
    current->next=NULL;
    current = first;
    while(current){
        printf("Account %05d:\t$%0.2f\n",current->account, current->balance);
        current=current->next;
    }
  return 0;
}
void fill_structure(struct stats *s){
    printf("Account number:");
    scanf("%d", &s->account);
    printf("Balance: $");
    scanf("%f", &s->balance);
    s->next=NULL;
}
struct stats *create(void){
    struct stats *baby;
    baby = (struct stats *)malloc(sizeof(struct stats));
    if(baby ==NULL){
        puts("Memory error");
        exit(1);
    }
    return baby;
};