Question:C program for area of a sphere 

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

int main(){

    float r;
    float surface_area,volume;

    printf("Enter radius of the sphere : ");
    scanf("%f",&r);

    surface_area =  4* M_PI * r * r;
    volume = (4.0/3) * M_PI * r * r * r;

    printf("Surface area of sphere is: %.3f",surface_area);
    printf("\nVolume of sphere is : %.3f",volume);

    return 0;
}
Sample output:
Enter radius of the sphere: 5
Surface area of sphere is: 314.159
Volume of sphere is: 523.599

Question:How to get multiplication of two very large numbers larger or beyond than long int in c programming language 

#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#include<string.h>
#define MAX 10000

char * multiply(char [],char[]);
int main(){
    char a[MAX];
    char b[MAX];
    char *c;
    int la,lb;
    int i;
    printf("Enter the first number : ");
    scanf("%s",a);
    printf("Enter the second number : ");
    scanf("%s",b);
    printf("Multiplication of two numbers : ");
    c = multiply(a,b);
    printf("%s",c);
    return 0;
}

char * multiply(char a[],char b[]){
    static char mul[MAX];
    char c[MAX];
    char temp[MAX];
    int la,lb;
    int i,j,k=0,x=0,y;
    long int r=0;
    long sum = 0;
    la=strlen(a)-1;
        lb=strlen(b)-1;
   
        for(i=0;i<=la;i++){
                a[i] = a[i] - 48;
        }

        for(i=0;i<=lb;i++){
                b[i] = b[i] - 48;
        }

    for(i=lb;i>=0;i--){
         r=0;
         for(j=la;j>=0;j--){
             temp[k++] = (b[i]*a[j] + r)%10;
             r = (b[i]*a[j]+r)/10;
         }
         temp[k++] = r;
         x++;
         for(y = 0;y<x;y++){
             temp[k++] = 0;
         }
    }
   
    k=0;
    r=0;
    for(i=0;i<la+lb+2;i++){
         sum =0;
         y=0;
         for(j=1;j<=lb+1;j++){
             if(i <= la+j){
                 sum = sum + temp[y+i];
             }
             y += j + la + 1;
         }
         c[k++] = (sum+r) %10;
         r = (sum+r)/10;
    }
    c[k] = r;
    j=0;
    for(i=k-1;i>=0;i--){
         mul[j++]=c[i] + 48;
    }
    mul[j]='\0';
    return mul;
}
Sample output of above code:
Enter the first number: 55555555
Enter the second number: 3333333333
Multiplication of two numbers:
185185183314814815

Question:How to get division of two very large numbers larger or beyond than long int in c programming language. 

#include<stdio.h>
#include<string.h>
#define MAX 10000

int validate(char []);
char * division(char[],long);
long int remainder;

int main(){

    char dividend[MAX],*quotient;
    long int divisor;

    printf("Enter dividend: ");
    scanf("%s",dividend);
    if(validate(dividend))
         return 0;

    printf("Enter divisor: ");
    scanf("%ld",&divisor);

    quotient = division(dividend,divisor);

    while(*quotient)
         if(*quotient ==48)
             quotient++;
         else
             break;

    printf("Quotient: %s / %ld  =  %s",dividend,divisor,quotient);
    printf ("\nRemainder: %ld",remainder);
    return 0;
}

int validate(char num[]){
    int i=0;

    while(num[i]){
         if(num[i] < 48 || num[i]> 57){
             printf("Invalid positive integer: %s",num);
             return 1;
         }
         i++;
    }

    return 0;
}

char * division(char dividend[],long divisor){
   
    static char quotient[MAX];
    long temp=0;
    int i=0,j=0;

    while(dividend[i]){
        
         temp = temp*10 + (dividend[i] -48);
         if(temp<divisor){
            
             quotient[j++] = 48;
            
         }
         else{
             quotient[j++] = (temp / divisor) + 48;
             temp = temp % divisor;

         }
         i++;
    }

    quotient[j] = '\0';
    remainder = temp;
    return quotient;
}
Sample output:
Enter dividend: 543109237823560187
Enter divisor: 456
Quotient: 543109237823560187 / 456 = 1191029030314824
Remainder: 443Alternate program (source code):
#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#include<string.h>
#define MAX 10000

char * division(char [],unsigned long);
int main(){
    char a[MAX];
    unsigned long b;
    char *c;
    printf("Enter the divdend : ");
    scanf("%s",a);
    printf("Enter the divisor : ");
    scanf("%lu",&b);
    c = division(a,b);
    printf("\nQuotient of the division : ");
    printf("%s",c);
    return 0;
}

char * division(char a[],unsigned long b){
    static char c[MAX];
    int la;
    int i,k=0,flag=0;
    unsigned long temp=1,reminder;
    la=strlen(a);

    for(i=0;i<=la;i++){
         a[i] = a[i] - 48;
    }

    temp = a[0];
    reminder = a[0];
    for(i=1;i<=la;i++){
         if(b<=temp){
             c[k++] = temp/b;
             temp = temp % b;
             reminder = temp;
             temp =temp*10 + a[i];
             flag=1;

         }
         else{
             reminder = temp;
             temp =temp*10 + a[i];
             if(flag==1)
                 c[k++] = 0;
         }
    }

    for(i=0;i<k;i++){
         c[i]=c[i]+48;
    }
    c[i]= '\0';

    printf("Reminder of division:  %lu  ",reminder);
    return c;
}
Sample output:
Enter the divdend:
55555555555555555555555555555555555555555
Enter the divisor: 5
Reminder of division:  0
Quotient of the division:
11111111111111111111111111111111111111111

Question:How to get modular division of two very large numbers larger or beyond than long int in c programming language 

#include<stdio.h>
#include<string.h>
#define MAX 10000

int validate(char []);
int modulerDivision(char[],unsigned long);


int main(){

    char dividend[MAX];
    unsigned long int divisor,remainder;

    printf("Enter dividend: ");
    scanf("%s",dividend);
    if(validate(dividend))
         return 0;

    printf("Enter divisor: ");
    scanf("%lu",&divisor);

    remainder = modulerDivision(dividend,divisor);

    printf("Modular division: %s %% %lu  =  %lu",dividend,divisor,remainder);

    return 0;
}

int validate(char num[]){
    int i=0;

    while(num[i]){
         if(num[i] < 48 || num[i]> 57){
             printf("Invalid positive integer: %s",num);
             return 1;
         }
         i++;
    }

    return 0;
}

int modulerDivision(char dividend[],unsigned long divisor){
   
    unsigned long temp=0;
    int i=0;

    while(dividend[i]){
        
         temp = temp*10 + (dividend[i] -48);
         if(temp>=divisor){
             temp = temp % divisor;
         }
   
         i++;
    }

    return temp;
}
Sample output:
Enter dividend: 123456789
Enter divisor: 56
Modular division: 123456789 % 56 = 29

Question:How to get power of two very large numbers larger or beyond than long int in c programming language 

#include<stdio.h>
#include<string.h>
#define MAX 10000

char * multiply(char [],char[]);
int main(){
    char a[MAX];
    char *c;
    int i,n;
    printf("Enter the base number: ");
    scanf("%s",a);
    printf("Enter the power: ");
    scanf("%d",&n);

    printf("Power of the %s^%d: ",a,n);

    c = multiply(a,"1");
    for(i=0;i<n-1;i++)
         c = multiply(a,c);

    while(*c)
    if(*c =='0')
         c++;
    else
         break;

    printf("%s",c);
    return 0;
}

char * multiply(char num1[],char num2[]){
    static char mul[MAX];
    char a[MAX];
    char b[MAX];
    char c[MAX];
    char temp[MAX];
    int la,lb;
    int i=0,j,k=0,x=0,y;
    long int r=0;
    long sum = 0;
   

    while(num1[i]){
         a[i] = num1[i];
         i++;
    }
    a[i]= '\0';

    i=0;
    while(num2[i]){
         b[i] = num2[i];
         i++;
    }
    b[i]= '\0';

    la=strlen(a)-1;
        lb=strlen(b)-1;
  
        for(i=0;i<=la;i++){
                a[i] = a[i] - 48;
        }

        for(i=0;i<=lb;i++){
                b[i] = b[i] - 48;
        }

    for(i=lb;i>=0;i--){
         r=0;
         for(j=la;j>=0;j--){
             temp[k++] = (b[i]*a[j] + r)%10;
             r = (b[i]*a[j]+r)/10;
         }
         temp[k++] = r;
         x++;
         for(y = 0;y<x;y++){
             temp[k++] = 0;
         }
    }
  
    k=0;
    r=0;
    for(i=0;i<la+lb+2;i++){
         sum =0;
         y=0;
         for(j=1;j<=lb+1;j++){
             if(i <= la+j){
                 sum = sum + temp[y+i];
             }
             y += j + la + 1;
         }
         c[k++] = (sum+r) %10;
         r = (sum+r)/10;
    }
    c[k] = r;
    j=0;
    for(i=k-1;i>=0;i--){
         mul[j++]=c[i] + 48;
    }
    mul[j]='\0';
    return mul;
}
Sample output:
Enter the base number: 5
Enter the power: 100
Power of the 5^100: 78886090522101180541172856528278622
96732064351090230047702789306640625

Question:C program for atm machine 

#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

Question:How to pass one dimensional array to function in c 

#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]);
}
}
}

Question:How to pass two dimensional array to a function in c 

#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");
   }
}

Question:Write a c program which takes password from users 

#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,

Question:Write a scanf function in c programming language which accept sentence from user 

#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?