#include <stdio.h>
#define M 3
#define N 5
void fstore2D(int a[][N]);
void fretrieve2D(int a[][N]);
int main(){
  int a[M][N];
  printf("Input data in matrix (%d X %d)\n", M, N);
  fstore2D(a);
  fretrieve2D(a);
  return 0;
}
void fstore2D(int a[][N]){
    int i, j;
    for (i = 0; i < M; ++i){
    for (j = 0; j < N; ++j)
         scanf("%d", &a[i][j]);
    }
}
void fretrieve2D(int a[][N]){
   int i, j;
   for ( i = 0; i < M; ++i ){
       for ( j = 0; j < N; ++j)
            printf("%6d ", a[i][j]);
       printf("\n");
   }
}

#include<stdio.h>
#define MAX 500

int main(){

    char password[MAX];
    char p;
    int i=0;

    printf("Enter the password:");
   
    while((p=getch())!= 13){
         password[i++] = p;
         printf("*");
    }

    password[i] = '\0';
    if(i<6)
         printf("\nWeak password");
    printf("\nYou have entered: %s",password);
    return 0;
}
Sample output:
Enter the password:*******
You have entered: fgt67m,

#include<stdio.h>
#define MAX 500

int main(){

    char arr[MAX];

    printf("Enter any sentence which can include spaces.\n");
    printf("To exit press enter key.\n");
    scanf("%[^\n]s",arr);

    printf("You had entered: \n");
    printf("%s",arr);

    return 0;
}
Sample output:
Enter any sentence which can include spaces.
To exit press enter key.
May I help you?
You had entered:
May I help you?

#include<stdio.h>
#define MAX 500

int main(){

    char arr[MAX];

    printf("Enter any paragraph which can include spaces or new line.\n");
    printf("To exit press the tab key.\n");
    scanf("%[^\t]s",arr);

    printf("You had entered: \n");
    printf("%s",arr);

    return 0;
}
Sample output:
Enter any paragraph which can include spaces or new line.
To exit, press the tab key.
C is powerful language.
I am learning c from
cquestionbank.blogspot.com

You had entered:
C is powerful language.
I am learning c from
cquestionbank.blogspot.com

#include <math.h>
#include <stdio.h>
main(){
  int i, j;
  i = 2;
  while ( i < 300 ){
     j = 2;
     while ( j < sqrt(i) ){
         if ( i % j == 0 )
            break;
         else{
            ++j;
            continue;
         }
      }
      if ( j > sqrt(i) )
            printf("%d\t", i);
      ++i;
  }
  return 0;
}