Matrix Multiplication By Using Pointer and Array

#include<stdio.h>
#include<windows.h>

void input(int *ptr);
void outpt(void);
void cal(void);

/*Declaring Global variable*/
int a[2][2],b[2][2],c[2][2],sum,i,j,k;


void main()
{
    int *p;
    p=a;
    printf("Enter First Matrix Elements :\n");
    input(p);/*Calling input() function for input*/
    printf("\n\n");
    p=b;
    printf("Enter Second Matrix Elements :\n");
    input(p);/*Calling input() function for input*/
    cal();/*Calling cal() for multiplication*/
    printf("\n\n");/*printing two new line*/
    printf("Multiplication of two matrix:\n\n\n");
    outpt();/*printing output*/

}


void input(int *ptr)/*input user define function*/
{
    for(i=0;i<2;i++)
    {
        for(j=0;j<=1;j++)
        {
            scanf("%d",&*ptr);
            ptr++;
        }
    }
}

void cal(void)/*cal user define function*/
{
    for(i=0;i<2;i++)
    {
        for(j=0;j<=1;j++)
        {
            sum=0;
            for(k=0;k<2;k++)
            {
               sum+=a[i][k]*b[k][j];
            }
            c[i][j]=sum;
        }
    }
}

void outpt(void)/*output user define function*/
{
    for(i=0;i<2;i++)
    {
        for(j=0;j<2;j++)
        {
            printf("%6d ", c[i][j]);
            Sleep(1000);
        }
        printf("\n\n");
    }

}

Pyramid by number in C language

#include <stdio.h>

void main()
{
    int p, q, m, n;

    printf("\n How many line do you want: ");
    scanf("%d", &n);

    printf("\n\n");
    for ( p = 1; p <= n; p++)
    {
        for (q = 1; q <= (n-p); q++)
        {
          printf("     ");
        }
        m = p;
        for(q = 1; q <= p; q++)
        {
            printf("%5d", m++);
        }
        m -= 2;
        for( q = 1; q < p; q++)
        {
           printf("%5d", m--);
        }
    printf("\n");
    }
    return 0;
}

Calculating Ratio In C language

#include <stdio.h>

void main()
{
    int p, q, r, s;
    float ratio;

    printf("\n Enter four integers ( seperates by space): ");
    scanf("%d %d %d %d", &p, &q, &r, &s);

    if ( (r-s) == 0 )
        {
        printf("\n Ratio is infinity, because (r-s) is 0.");
        exit(0);
        }

    else
        {
        ratio = (float)(p+q) / (float) (r-s);
        printf("\n Ratio is %.2f", ratio);
        }

   return 0;
}

Convert gallon to litter in C language

#include <stdio.h>


void main()
{
    float gallon,litter;

    printf("\n\n");
    printf("\t\tGallon       Litre");
    printf("\n\t\t......       ......");


    for(gallon=1; gallon<=10; gallon++)
    {
       litter = gallon*3.785;
       printf("\n\t\t%5.2f        %5.2f", gallon, litter);
    }
    printf("\n\n");
    return 0;
}

Decimal to Binary in C language

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

void main()
{
    long int d_n, rem, b_n = 0, base=1;
    printf("Enter a decimal number : ");
    scanf("%ld",&d_n);
    printf("\n\n\nYour entered decimal number is : %ld",d_n);
    while(d_n!=0)
    {
        rem=d_n%2;
        b_n+=rem*base;
        base*=10;
        d_n/=2;
    }

    printf("\nYahoo Your entered decimal number is converted into binary");
    printf("\nAnd the number is : %ld",b_n);

    return 0;
}

Area triangle in C language

#include <stdio.h>

void main()
{
    float a,b,c;
    float p,area,s;

    a=5;
    b=5;
    c=6;

    s =((a+b+c)/2);
    p = (s*(s-a)*(s-b)*(s-c));
    area = pow(p,.5);
    printf("area is %f", area);

}

Addition Subtraction Multiplication Division in C Language

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

int main()
{
    char latter;
    printf("What operation you want to do?\n\t A)Addition\n\t B)Subtraction\n\t C)Multiplication\n\t D)Division\n\n\nEnter Your Choice: ");
    scanf("%c", &latter);
    float num1, num2;
    printf("\n\tplease enter the first number: ");
    scanf("%f", &num1);
    printf("\n\tplease enter the second number: ");
    scanf("%f", &num2);
    if(latter == 'A' || latter == 'a')
        printf("\n\tthe sum is %.2f", num1+num2);
    else if(latter == 'B' || latter == 'b')
        printf("\n\tthe difference is %.2f", num1-num2);
    else if(latter == 'C' || latter == 'c')
        printf("\n\tthe multiplication is %.2f", num1*num2);
    else if(latter == 'D' || latter == 'd')
        printf("\n\tthe division is %.2f", num1/num2);
    else
        printf("\n\tyou entered a invalid character");

    return 0;
}

Prepaid Monthly Calling System

/*Here is a program for a post paid customer .where every call cost is 1.25 tk.its a fully postpaid calling system where customer have a monthly limit but he can use how much he want to use. */

#include<stdio.h>

void main()

{

    float rbill=0,blnc,time,tmp_time=0;

    char ch;

    printf("Enter your monthly postpaid limit in taka: ");

    scanf("%f", &blnc);

    loop:

        {

            do

    {

        printf("\n\n");

        printf("Press for a call...");

        getch();

        printf("\nEnter your call time: ");

        scanf("%f", &tmp_time);

        time+=tmp_time;

        rbill+=(tmp_time*1.25);

        printf("Your total call time: %.2f minute.\nYour total bill: %.2f taka.",time,rbill);

    }while(rbill<blnc);

    printf("\n\nSorry You Have Crossed Your Monthly Limit.\nYou have used %.2f extra balance from your limit\n\n", (rbill-blnc));

    printf("If you still want to call press 'c' or 'C' key or Any key to end : ");

    scanf("%s", &ch);

    if(ch=='c'||ch=='C')

    {

        goto loop;

    }

    else

    {

        printf("Program end.");

    }

        }

}

Matrix Multiplication In C

#include<stdio.h>

void main()
{
    int c[2][2],i,j,k,sum=0;
    int a[2][2] = { {5,4},
                    {4,4} };
    int b[2][2] = { {6,7},
                    {4,8} };
    printf("The matrix A is :\n\n\t\t");
    for(i=0;i<2;i++)
    {
        for(j=0;j<2;j++)
        {
            printf("%d\t",a[i][j]);
        }
        printf("\n\t\t");
    }
    printf("\nThe matrix B is :\n\n\t\t");
    for(i=0;i<2;i++)
    {
        for(j=0;j<2;j++)
        {
            printf("%d\t",b[i][j]);
        }
        printf("\n\t\t");
    }
    printf("\nMultiplication of A and B matrix is: \n\n\t\t");
    for(i=0;i<2;i++)
    {
        for(j=0;j<2;j++)
        {
            for(k=0;k<2;k++)
            {
                sum+=(a[i][k]*b[k][j]);
            }
            c[i][j]=sum;
            printf("%d\t",c[i][j]);
        }
        printf("\n\t\t");
    }
}