C programs

bin_oct_hex_dec.c

// [binary-Hex-Octal-dec] conversions

//10101010

#include <stdio.h>
int main()
{
    unsigned long int val=10101011;
    long int rem=0x00,i=1,out=0;
    while(val !=0)
    {
        rem= val%10;
      // printf("val:%x\n",val);
      //  printf("reminder:%d\n",rem);
        out=out+(rem*i);
        i=i*2;
        val=val/10;


    }
    printf("the DEC val:%d\n",out);
    printf("the HEX val:%X\n",out);
    printf("the OCT val:%o",out);
}

clr_set_toggle_bit.c

#include <stdio.h>
int main()
{
    unsigned long int input=0,result =0;
    int clear_bit=2;
    input=0xff;
    result=input;
    result&=~(1<<clear_bit); // result|=(1<<clear_bit)  // result^=(1<<clear_bit)
    clear_bit+=4;
    result&=~(1<<clear_bit);
    printf("the resutl:%lo",result);
}

diamond.c

#include <stdio.h>     //Diamond Pattern !!!

void main()
{
    int i=0,j=0,k=0,space=0,dec=9,inc=1,q=0;
    for(k=5;k>0;k--)
    {
        dec-=2;
        for(space=dec;space>=0;space--)
        {
         printf(" ");
         }

        for(i=1;i<=inc;i++)
        {
            printf("%d ",i);
        }
        q=i-1;
            while(q>1)
            {
                printf("%d ",q-1);
                q--;
            }
        inc++;
        printf("\n");
    }
    dec=-1;
    inc=5;
    for(k=5;k>0;k--)
    {
        dec+=2;
        for(space=dec;space>=0;space--)
        {
         printf(" ");
         }

        for(i=1;i<inc;i++)
        {
            printf("%d ",i);
        }
        q=i-1;
            while(q>1)
            {
                printf("%d ",q-1);
                q--;
            }
        inc--;
        printf("\n");
    }
        
}

l_r_shift.c

// Right shift and Left shift


#include <stdio.h>
#include <stdint.h>

int main()
{
    signed int val=16,shift =0,k=1;
     // shift=(val<<k);
    for (int i=sizeof(val)*8-1;i>=0;i--)
    {
        printf("%d",(val & (1<<i)) >>i);

        if(i%4 == 0)
            printf(" ");
    }
    //printf("output:%d",shift);
    return 0;

}

little_big_endian.c

#include <stdio.h>
#include <stdint.h>
union check{
    uint8_t a;
    uint32_t arr[2];

};

void main()
{
union check t1;
t1.a=1;
if(t1.arr[0] == 1)
    printf("Little Endian");
else if(t1.arr[0] == 0)
    printf("Big Endian");
}

nibble_shift.c

//Nibble shift of a value


#include <stdio.h>


int main()
{
    unsigned int val=0xab,out=0;
    out=(val & 0xf0)>>4 |(val & 0x0f)<<4 ;

    for(int i=sizeof(out)*8-1;i>=0;i--)
    {
        printf("%d",(out & (1<<i)) >> i);

        if(i%4==0)
        printf(" ");
    }
    printf("\nThe Nibble shift value:%X",out);
}

pattern_1.c

 /* 5 \n 5 4 \n 5 4 3 \n 5 4 3 2 \n 5 4 3 2 1 */
#include <stdio.h>            
void main()
{
    int i=0,j=0,k=0,count=5;
    for (i=1;i<=5;i++)
    {
        count--;
        for(j=5;j>count;j--)
        {
            printf("%d ",j);
        }
        printf("\n");
    }
}

pattern_2.c

#include <stdio.h>                /* 5 \n 4 5 \n 3 4 5 \n 2 3 4 5 \n 1 2 3 4 5 */
void main()
{
    int i=0,j=0,count=0;
    for(int i=5;i>=1;i--)
    {
        count++;
        for(j=i;j<=5;j++)
        {
         printf("%d ",j);
        }
        printf("\n");
    }
}

pattern_3.c

#include <stdio.h>               /* 1 2 3 4 5 \n 1 2 3 4 \n 1 2 3  \n 1 2 \n 1 */
void main()
{
    int i=0,j=0,count=5;
    for(i=1;i<=5;i++)
    {
        
        for(j=1;j<=count;j++)
        {
            printf("%d ",j);
        }
        count--;
        printf("\n");
    }
}

ptrs_1.c

/* pointers example a=a+b
                    b=|a-b|
*/
#include <stdio.h>
#include <math.h>

void update(int *a,int *b) {
    // Complete this function  
    int sum=0,diff=0,n;
    sum=*a+*b;
    diff=*a-*b;
    if(diff*=-1 > diff)   //diff=abs(diff);
    {
        diff=diff*-1;
    }
    *a=sum;
    *b=diff;
      
}

int main() {
    int a=5, b=10;
    int *pa = NULL, *pb = NULL;
    pa=&a;pb=&b;
    printf("the address of a:%d and b :%d\n",pa,pb);
    update(pa, pb);
    printf("%d\n%d", a, b);

    return 0;
}

rev_2.c

#include <stdio.h>

char* reverse(char *sp)
{
   int i=0,j=0,count=0;
    static char test[100]={0};
    
    while(sp[i] !='\0')
    {
        count++;
        i++;
    }
    i=count;
    while(i>0 )
    {
        test[j]=sp[i-1];
       // sp[j]=test[i-1];
        i--;
        j++;
    }
    char *tes=test;
    return tes;
    

}

void main()
{
unsigned char val[]="Hello krishnakanth how are you !!!";
char *sp;
sp=val;
reverse(sp);
printf("the string reverse:%s",reverse(sp));
}

rev_num.c

/* Reverse a number*/

#include <stdio.h>
int main ()
{
    int output=0,input=0,rem=0;;
    printf("Enter the number:");
    scanf("%d",&input);
    while(input != 0)
    {
        rem=input%10;
        output=output*10+rem;
        input=input/10;

    }
    printf("\n the output is:%d", output);
    printf("\n rem:%d", rem);
    getchar();
    return 0;
}

str_rev.c

/* string reverse */

#include <stdio.h>
#include <string.h>
void main()
{
    char input[100];
    char output[100];
    int count=0,i=0;
    printf("enter the string:");
    scanf("%s",input);
    int val=strlen(input);
    while(input[i] != '\0')
    {
        count++;
        i++;
    }
    printf("val:%d\n",val);
    printf("count:%d\n",count);
    for(int i=val-1,j=0;i>=0,j<=val-1;i--,j++)
    output[j]=input[i];
    printf("\n");
    printf("reverse of the string:");
    printf("%s",output);
}

str_rev_ptr.c

#include <stdio.h>   // String rev using function call and pointers
void strrev(char *ch)
{
    char rev[100];
    int i=0,count=0,set=0;
    while(ch[i] != '\0')
    {
       // count++;
        i++;
    }
    while(i>0)
    {
        rev[count]=ch[i-1];
        i--;
        count++;
    }

    printf("size of a string:%d\n",i);
    printf("the orginal string:%s\n",ch);
    printf("the rev of string:%s\n",rev);
    printf("last val:%d",ch[count]);

}
void main()
{
unsigned char str[]="hello krishnakanth S";char *a;
a=str;
strrev(a);

char a[10]="Hello";
strrev(a);
printf("%s",a); //olleH
}

struct_bit_fields.c

#include <stdio.h>
#include <stdint.h>

struct date{
    uint16_t d:5;
    uint8_t m:4;
    uint16_t y;
};//__attribute__((packed))

void main()
{
    struct date d1;
    uint8_t size= sizeof(d1);
    d1.d=15;
    d1.m=12;
    d1.y=2021;
    printf("the date mentioned as: %d/%d/%d.",d1.d,d1.m,d1.y);
    printf("\nsize of structure:%d", size);
}

struct_bit_fields_2.c

#include <stdio.h>
#include <stdint.h>

union test{
    uint32_t a;
    struct {
        uint8_t p;
        uint8_t q;
        uint8_t r;
        uint8_t s;
    }z;

    struct {
        uint8_t m:8;
        uint8_t n:4;
        uint8_t o:4;
        uint8_t p:4;
        uint8_t q:4;
    }y;

        struct {
            uint8_t b:1;
    }x;
};


int main()
{

    uint16_t a = 0xAB;
    union test t2;
    printf("%d\n", sizeof(t2.x));
    //1010 1011

    union test t1;
    t1.a =  0xABCDEF11;
    printf("%x %x %x %x \n", t1.z.p, t1.z.q, t1.z.r, t1.z.s );
    printf("%d %d %d %d %d\n", t1.y.m, t1.y.n, t1.y.o,t1.y.p,t1.y.q);


    // i =7 
    // 1
    // i =6   
    // 0 == > a & (1<<i) >> i
    // 0010 0000

    for(int i=sizeof(a)*8 -1 ; i>=0; i--)
    {
        printf("%d", (a & (1<<i)) >> i);

        if(i%4 == 0)
            printf(" ");    
    }


    return 0;
}