What would be the output of the following program ?

main()

{

     const int x = 5; 

      int *ptrx;

      ptrx = &x;

      *ptr = 10;

       printf ("%d", x);

}

#include<stdio.h>
int main(){
  int num,i,f,r,sum=0,temp;

  printf("Enter a number: ");
  scanf("%d",&num);
 
  temp=num;
  while(num){
      i=1,f=1;
      r=num%10;

      while(i<=r){
         f=f*i;
        i++;
      }
      sum=sum+f;
      num=num/10;
  }
  if(sum==temp)
      printf("%d is a strong number",temp);
  else
      printf("%d is not a strong number",temp);

  return 0;
}

Sample output:
Enter a number: 145
145 is a strong number

 #include<stdio.h>
int main(){
  int i=1,f=1,num;

  printf("Enter a number: ");
  scanf("%d",&num);

  while(i<=num){
      f=f*i;
      i++;
  }

  printf("Factorial of %d is: %d",num,f);
  return 0;
}

Sample output:
Enter a number: 5
Factorial of 5 is: 120

 #include<stdio.h>
int main(){
    int num,r,sum=0,temp;

    printf("Enter a number: ");
    scanf("%d",&num);

    temp=num;
    while(num){
         r=num%10;
         num=num/10;
         sum=sum*10+r;
    }
    if(temp==sum)
         printf("%d is a palindrome",temp);
    else
         printf("%d is not a palindrome",temp);

    return 0;
}

Sample output:
Enter a number: 131
131 is a palindrome

 #include<stdio.h>
int main(){
    int k,r;
    long int i=0l,j=1,f;

    //Taking maximum numbers form user
    printf("Enter the number range:");
    scanf("%d",&r);

    printf("FIBONACCI SERIES: ");
    printf("%ld %ld",i,j); //printing firts two values.

    for(k=2;k<r;k++){
         f=i+j;
         i=j;
         j=f;
         printf(" %ld",j);
    }
 
    return 0;
}

Sample output:
Enter the number range: 15
FIBONACCI SERIES: 0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

#include<stdio.h>
int main(){
    int a=5,b=10;
    a=b+a;
    b=a-b;
    a=a-b;
    printf("a= %d  b=  %d",a,b);
}

It is also called as post tested loop. It is used when it is necessary to execute the loop at least one time. Syntax:

do {
Loop body
} while (Expression);

Example:

int main(){
    int num,i=0;  
    do{
         printf("To enter press 1\n");
         printf("To exit press  2");
         scanf("%d",&num);
         ++i;
         switch(num){
             case 1:printf("You are welcome\n");break;
             default : exit(0);
         }
    }
    while(i<=10);
    return 0;
}

Output: 3 3 4 4

#include
int main( int count,char * argv[] ) {
    int i;
    FILE *ptr;
    char *str;
    char ch;
    if( count == 1) {

         printf( "The syntax of the command is incorrect.\n" );
    }
    for( i=1;i<cout;i++ ){
         ptr=fopen(argv[i],"r");
         if(ptr==NULL){
             printf("The system cannot find the file specified.");
             if(count>2)
                 printf("\nError occurred while procesing : %s.\n",argv[i]);
         }
         else {
             if(count>2) {
                 printf("%s\n\n",argv[i]);
             }
             while((ch=getc(ptr))!=-1)
                 printf("%c",ch);
         }
         fclose(ptr);
    }
    return 0;
}

Save the above file as open.c, compile and execute the go to command mode (current working directory) and write: open xy.c (xy.c any file present in that directory)
To run the open command in all directories and drive you will have to give the path of current working directory in command mode. Write:
C:tc\bin>PATH c:\tc\bin
Now press enter key. Now your open command will work in all directory and drive.

Size of any array in c cannot be constantan variable.