C program to add, subtract, multiply and divide Complex Numbers, complex arithmetic

Asked in Honeywell Technical Interview:

C Program to add, subtract, multiply and divide complex numbers :- This program performs basic operations on complex numbers i.e addition, subtraction, multiplication and division. This is a menu driven program in which user will have to enter his/her choice to perform an operation. User can perform operations until desired. To easily handle a complex number a structure named complex has been used, which consists of two integers first integer is for real part of a complex number and second for imaginary part.

#include
#include
#include

struct complex
{
int real;
int img;
};

main()
{
int choice, temp1, temp2, temp3;
struct complex a, b, c;

while(1)
{
clrscr();
printf("Press 1 to add two complex numbers.\n");
printf("Press 2 to subtract two complex numbers.\n");
printf("Press 3 to multiply two complex numbers.\n");
printf("Press 4 to divide two complex numbers.\n");
printf("Press 5 to exit.\n");
printf("Enter your choice ");
scanf("%d",&choice);

if( choice == 5)
exit(0);

if(choice >= 1 && choice <= 4) { printf("Enter a and b where a + ib is the first complex number."); printf("\na = "); scanf("%d", &a.real); printf("b = "); scanf("%d", &a.img); printf("Enter c and d where c + id is the second complex number."); printf("\nc = "); scanf("%d", &b.real); printf("d = "); scanf("%d", &b.img); } if ( choice == 1 ) { c.real = a.real + b.real; c.img = a.img + b.img; if ( c.img >= 0 )
printf("Sum of two complex numbers = %d + %di",c.real,c.img);
else
printf("Sum of two complex numbers = %d %di",c.real,c.img);
}
else if ( choice == 2 )
{
c.real = a.real - b.real;
c.img = a.img - b.img;

if ( c.img >= 0 )
printf("Difference of two complex numbers = %d + %di",c.real,c.img);
else
printf("Difference of two complex numbers = %d %di",c.real,c.img);
}
else if ( choice == 3 )
{
c.real = a.real*b.real - a.img*b.img;
c.img = a.img*b.real + a.real*b.img;

if ( c.img >= 0 )
printf("Multiplication of two complex numbers = %d + %di",c.real,c.img);
else
printf("Multiplication of two complex numbers = %d %di",c.real,c.img);
}
else if ( choice == 4 )
{
if ( b.real == 0 && b.img == 0 )
printf("Division by 0 + 0i is not allowed.");
else
{
temp1 = a.real*b.real + a.img*b.img;
temp2 = a.img*b.real - a.real*b.img;
temp3 = b.real*b.real + b.img*b.img;

if ( temp1%temp3 == 0 && temp2%temp3 == 0 )
{
if ( temp2/temp3 >= 0)
printf("Division of two complex numbers = %d + %di",temp1/temp3,temp2/temp3);
else
printf("Division of two complex numbers = %d %di",temp1/temp3,temp2/temp3);
}
else if ( temp1%temp3 == 0 && temp2%temp3 != 0 )
{
if ( temp2/temp3 >= 0)
printf("Division of two complex numbers = %d + %d/%di",temp1/temp3,temp2,temp3);
else
printf("Division of two complex numbers = %d %d/%di",temp1/temp3,temp2,temp3);
}
else if ( temp1%temp3 != 0 && temp2%temp3 == 0 )
{
if ( temp2/temp3 >= 0)
printf("Division of two complex numbers = %d/%d + %di",temp1,temp3,temp2/temp3);
else
printf("Division of two complex numbers = %d %d/%di",temp1,temp3,temp2/temp3);
}
else
{
if ( temp2/temp3 >= 0)
printf("Division of two complex numbers = %d/%d + %d/%di",temp1,temp3,temp2,temp3);
else
printf("Division of two complex numbers = %d/%d %d/%di",temp1,temp3,temp2,temp3);
}

}

}
else
printf("Invalid choice.");

printf("\nPress any key to enter choice again...");
getch();
}
}

Posted in: C