#include<stdio.h>

int totalThousand =1000;
int totalFiveFundred =1000;
int totalOneHundred =1000;

int main(){

    unsigned long withdrawAmount;
    unsigned long totalMoney;

    int thousand=0,fiveHundred=0,oneHundred=0;

    printf("Enter the amount in multiple of 100: ");
    scanf("%lu",&withdrawAmount);

    if(withdrawAmount %100 != 0){
         printf("Invalid amount;");
         return 0;
    }

    totalMoney = totalThousand * 1000 + totalFiveFundred* 500 +  totalOneHundred*100;

    if(withdrawAmount > totalMoney){
         printf("Sorry,Insufficient money");
         return 0;
    }

    thousand = withdrawAmount / 1000;
    if(thousand > totalThousand)
         thousand = totalThousand;
    withdrawAmount = withdrawAmount - thousand * 1000;

    if (withdrawAmount > 0){
         fiveHundred = withdrawAmount / 500;
         if(fiveHundred > totalFiveFundred)
             fiveHundred = totalFiveFundred;
         withdrawAmount = withdrawAmount - fiveHundred * 500;
    }

    if (withdrawAmount > 0)
         oneHundred = withdrawAmount / 100;

    printf("Total 1000 note: %d\n",thousand);
    printf("Total  500 note: %d\n",fiveHundred);
    printf("Total  100 note: %d\n",oneHundred);

    return 0;
}
Sample output:
Enter the amount in multiple of 100: 7800
Total 1000 note: 7
Total  500 note: 1
Total  100 note: 3

#include <stdio.h>
#define N 5
void fstore1D(int a[], int a_size);
void fretrieve1D(int a[], int a_size);
void fedit1D(int a[], int a_size);
int main(){
int a[N];
printf("Input data into the matrix:\n");
fstore1D(a, N);
fretrieve1D(a, N);
fedit1D(a, N);
fretrieve1D(a, N);
return 0;
}

void fstore1D(int a[], int n){
int i;
for ( i = 0; i < n; ++i )
scanf("%d", &a[i]);
}

void fretrieve1D(int a[], int n){
int i;
for ( i = 0; i < n; ++i )
printf("%6d ", a[i]);
printf("\n");
}

void fedit1D(int a[], int n){
int i, q;
for ( i = 0; i < n; ++i ){
printf("Prev. data: %d\nEnter 1 to edit 0 to skip.", a[i]);
scanf("%d", &q);
if ( q == 1 ){
printf("Enter new value: ");
scanf("%d", &a[i]);
}
}
}

#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?