Thread: Need help with basic calculation program.

I changed a few things so the addition function works. I don't know if that's what you want, however.

Here's the code:

Code:

#include<stdio.h>

int main(void)
{
   /*Create variables.*/
   int number1, number2;
   int operation;
   int total;
   int cont;
   int result;

   do  {
      /*Ask the user if they'd like to start a new calculation.*/
      printf("Would you like to perform a new calculation? Enter 1 for [Yes] or 2 for [No].\n");
      scanf(" %i", &cont);
         
      /*If yes, set the total to zero.*/
      if(cont == 1)
      { 
         total = 0;
         /*Ask user to assign a value to "operation"*/
         printf("Please choose an operation. Enter 1 for [Addition], 2 for [Subtraction]");
         printf("3 for [Multiplication], or 4 for [Division])\n");
         scanf(" %i", &operation);

         /*If the operation is [1], begin the addition sequence.*/
         if(operation == 1)
         {
   	    /*Assign value to the number.*/
            printf("Enter the first integer that you'd like to add.\n");
   	    scanf(" %i", &number1);
            printf("Now enter the second integer to be added.\n");
            scanf(" %i", &number2);
      	    /*Add the numbers to find their sum.*/
      	    result = number1 + number2;
      	    /*Display the answer.*/
            printf("The sum is %d.\n", result);
      	    total = result;
         }
         /*Start the subtraction block if [2] is entered for operation.*/
         if(operation == 2)
         {  /*Assign value to the number.*/
            printf("Enter the integer you'd like to subtract.\n");
      	    scanf(" %i", &number1);
            /*Perform the subtraction operation.*/
            result = total - number1;
            /*Display the answer.*/
            printf("The difference is %d.\n", result);
      	    total = result;
        }

         /*If multiplication is chosen, start this block.*/
         if(operation == 3)
         {
         	/*Ask for a value to be assigned.*/
         	printf("Enter the integer that you'd like to multiply.\n");
         	scanf(" %i", &number1);

      		/*Perform the multiplication sequence.*/
   		result = 0;
   		while(number1 > 0)
		{
	   		result += total;
   			number1--;
		}
	
            /*Display the result.*/
         	printf("The product is %d.\n", result);
   	   	total = result;

         } //end of if operation == 3

         /*Division block for operation == 4.*/
         if(operation == 4)
         {
            /*Ask for a value to be assigned.*/
         	printf("Enter the integer that you'd like to divide by.\n");
         	scanf(" %i", &number1);
         	/*Perform the division operation.*/
   			while(total > 0)
   			{  total -= number1;
   				result++;
   			}

            /*Display the result.*/
            printf("The quotient is %d.\n", result);
   	    total = result;
         }
      } //end of if(cont == 1)
   }while(cont == 1);

   result = getchar();  //just holds the console window open
   return(0);
}

Weird, I thought I had a couple of more posts here but I don't see them.

Anyway, many thanks to everyone for the help. I really appreciate it, probably couldn't have gotten it done without some of your suggestions/fixes.

Here's the code that I ended up with:

Code:

#include<stdio.h>

int main(void)
{
/*Create variables.*/
	int number1;
	int operation;
	int total;
	int cont;
	int result;
	int loop = -1;

while(loop == -1)
{
/*Ask the user if they'd like to start a new calculation.*/
printf("Would you like to perform a new calculation? (Enter 1 for [Yes] or 2 for [No].)\nEnter 3 to [Terminate].\n");
scanf("%i", &cont);

/*Terminate the program if the user assigns [3] to cont.*/
if(cont == 3)
{
	return(0);
}
/*If yes, set the total to zero.*/
if(cont == 1)
{
	total = 0;
}

/*Ask user to assign a value to "operation"*/
printf("Please choose an operation. (Enter 1 for [Addition], 2 for [Subtraction], 3 for [Multiplication], or 4 for [Division])\n");
scanf("%i", &operation);

/*If the operation is [1], begin the addition sequence.*/
if(operation == 1)
{
/*Assign value to the number.*/
printf("Enter the integer that you'd like to add.\n");
scanf("%i", &number1);
/*Add the numbers to find their sum.*/
	result = total + number1;
/*Display the answer.*/
printf("The sum is %d.\n", result);
	total = result;
}

/*Start the subtraction block if [2] is entered for operation.*/
else if(operation == 2)
{
/*Assign value to the number.*/
printf("Enter the integer you'd like to subtract.\n");
scanf("%i", &number1);
/*Perform the subtraction operation.*/
	result = total - number1;
/*Display the answer.*/
printf("The difference is %d.\n", result);
	total = result;
}

/*If multiplication is chosen, start this block.*/
else if(operation == 3)
{
/*Ask for a value to be assigned.*/
printf("Enter the integer that you'd like to multiply.\n");
scanf("%i", &number1);
/*Perform the multiplication sequence.*/
	result = 0;
if(number1 > 0)
{
while(number1 > 0)
{
	result += total;
	number1--;
}
}
if(number1 < 0)
{
while(number1 < 0)
	result -= total;
	number1++;
}
	
/*Display the result.*/
printf("The product is %d.\n", result);
	total = result;
}

/*Division block for operation == 4.*/
else if(operation == 4)
{
/*Ask for a value to be assigned.*/
printf("Enter the integer that you'd like to divide by.\n");
scanf("%i", &number1);
/*Perform the division operation.*/
	result = 0;
if(total > 0)
{

if(number1 > 0)
{
while(total > 0)
{
	total -= number1;
	result++;
}
}
else if(number1 < 0)
{
while(total > 0)
{
	total += number1;
	result--;
}
}

}
else if(total < 0)
{

if(number1 > 0)
{
while(total < 0)
{
	total += number1;
	result++;
}
}
else if(number1 < 0)
{
while(total < 0)
{
	total -= number1;
	result++;
}
}

}
/*Display the result.*/
printf("The quotient is %d.\n", result);
	total = result;
}

else
{
printf("That command is not recognized.\n");
}
}

return(0);
}