// ----------------------------------------------------------

#include <stdio.h>
#include <math.h>

main()
{
  double a,b,c,d;

  printf("Input a, b, c: ");
  scanf("%lf %lf %lf",&a,&b,&c);

  if(a==0){
    if(b==0)
      printf("No Answer \n");
    else
      printf("X = %f\n",-c/b);
  } else {

    d = pow(b,2)-4*a*c;

    if(d<0)
      printf("X= Imaginary number\n");
    else if(d==0){
      printf("X= %8.3f\n",(-b+sqrt(d))/(2*a));
    }else{
      printf("X= %8.3f, %8.3f\n",(-b+sqrt(d))/(2*a),(-b-sqrt(d))/(2*a));
    }

  }
}

// ----------------------------------------------------------

#include <stdio.h>

void main()
{
  char sentence[128];
  int n=0,i;

  while(n<128){
    sentence[n]=getchar();
    if(sentence[n]=='\n')
      break;
    n++;
  }

  if(sentence[0] >= 'a' && sentence[01] <= 'z' )
    sentence[0] = sentence[0] + ('A'-'a');

  for(i=0;i<n+1;i++){
    
    switch(sentence[i]){

    case ' ':

      if(i+1<128){
	if(sentence[i+1] >= 'a' && sentence[i+1] <= 'z' ){
	  sentence[i+1] = sentence[i+1] + ('A'-'a');
	}
      }
    }
    
    printf("%c",sentence[i]);

  }
}

// ----------------------------------------------------------


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

void d2h(int num)
{
  if(0<=num&&num<10)
    printf("%d",num);
  else if(9<num && num<16)
    printf("%c",'a'+(num-10));
  else
    printf("X");
}

void d2h2(int num)
{
  int i,c=0;
  int k[32];
  
  while(num > 15){
    k[c]=num % 16;
    num = num/16;
    c++;
  }
  k[c]=num;
  for(i=4;i>=0;i--)
	  if(c<i)
		  printf(" ");
	  else
		d2h(k[i]);
 }

void main()
{
	int i,j;
	int m[4][4];

	srand(getpid());

	for(i=0;i<4;i++)
		for(j=0;j<4;j++)
			m[i][j]=rand()%65536;
			
	for(i=0;i<4;i++){
		for(j=0;j<4;j++)
			printf("%5d ",m[i][j]);
		printf("\n");
	}

	printf("\n");

	for(i=0;i<4;i++){
		for(j=0;j<4;j++){
			d2h2(m[i][j]);
			printf(" ");
		}
		printf("\n");
	}
}

// ----------------------------------------------------------

#include <stdio.h>
#include <math.h>

void d2h(int num)
{
  if(0<=num&&num<10)
    printf("%d",num);
  else if(9<num && num<16)
    printf("%c",'a'+(num-10));
  else
    printf("X");
}

void d2h2(int num)
{
  int i,c=0;
  int k[32];
  
  while(num > 15){
    k[c]=num % 16;
    num = num/16;
    c++;
  }
  k[c]=num;
  for(i=4;i>=0;i--)
	  if(c<i)
		  printf(" ");
	  else
		d2h(k[i]);
 }

int h2d(char h)
{
  int num=0;
  if('0'<=h&&h<='9')
    num = 0 + (h-'0');
  else if('a'<=h&&h<='f')
    num = 10 + (h-'a');
  else
    num = -1;
  return num;
}

int h2d2(char h[8],int n)
{
  int i,d=0,k;

  for(i=0;i<n;i++){
    k = h2d(h[i]);
    if(k == -1){
      printf("Invalid \n");
      return -1;
    }
    d = d +  k * (int)pow(16,n-1-i);
  }

  return d;
}

void main()
{
	char h0[8],h1[8];
	int n0,n1;

	printf("Input Hex: ");
	n0=0;
	while(n0<8){
    h0[n0]=getchar();
    if(h0[n0]=='\n')
      break;
    n0++;
  }

	printf("Input Hex: ");
	n1=0;
	while(n1<8){
    h1[n1]=getchar();
    if(h0[n1]=='\n')
      break;
    n1++;
  }
	
	if(h2d2(h0,n0)>=0&&h2d2(h1,n1)>=0)
		d2h2(h2d2(h0,n0)+h2d2(h1,n1));

	printf("\n");
}