if statements

[tquiva]

Hi could someone please help me with my code? I want to calculate an accumulate investment after a given amount of years, months, or days. I am reading in an annual interest from the user and would like to have this converted into monthly and daily interest based on the user's chosen type of compounding. I am using an if statement to do this. However, when I run the program, why do I received 3 sets of values for the 3 different types of compounding? I want to receive only 1 set, but I don't know what am I doing wrong?

/* File: account.c
 *     * Date: February 2, 2010 */

/* This program calculates the accumulated value of a given initial investment and annual interest, given the options of either annual, monthly, or daily
 * compounding */

#include <stdio.h>

/* Function declaration */
float calc_acc_amt(int x, float acc_amount, float annual_interest, int y);

main()
{
  /* Variable declarations */
  float initial; /* Input initial value of investment */
  float interest; /* Input annual interest */
  float input; /* User input of initial value and annual interest */
  int type; /* Input type of compounding */
  int start = 1; /* Used for start of loop in function */
  float acc_amt; /* Accumulated amount of investment invoked by function */
  float monthly_interest; /* Modified interest due to chosen input of monthly compounding */
  float daily_interest; /* Modified interest due to chosen input of daily compounding */
  int length; /* Length of compounding */

        /* Program intro */
        printf("This program will calculate the accumulated value of your investment at an annual, monthly, or daily compounding\n");

        /* Obtain input from user */
        printf("Please enter the following data, seperated by spaces.\n");
        printf("Initial value, annual interest: ");
        input = scanf("%f %f", &initial, &interest);

        printf("Type of compounding: (1) annually, (2) monthly, (3) daily: ");
        input = scanf("%d", &type);

        printf("Length of compounding: ");
        scanf("%d", &length);

                while (input != EOF) /* Initialize loop */
                {       if (type = 1)
                        {       /* Invoke function */
                                acc_amt = calc_acc_amt(start, initial, interest, length);

                        }
                        if (type = 2)
                        {
                                monthly_interest = (interest)/(12);
                                acc_amt = calc_acc_amt(start, initial, monthly_interest, length);
                        }
                        if (type = 3)
                        {
                                daily_interest = (interest)/(365);
                                acc_amt = calc_acc_amt(start, initial, daily_interest, length);
                        }
                        if (type != 1 || type != 2 || type != 3)
                        {
                                printf("Please indicate type of compound.");
                                break;
                        }

                        /* Update loop */
                         printf("Initial value, annual interest: ");
                        input = scanf("%f %f", &initial, &interest);

                        printf("Type of compounding: (1) annually, (2) monthly, (3) daily: ");
                        input = scanf("%d", &type);
                }

} /* End main */

/* Function */

float calc_acc_amt(int x, float acc_amount, float annual_interest, int y)

{float value;
      while (x <= y)
      { printf("%d: ", x);
        if (x != 1) /* when x is not equal to 1 */
        {
        value = value + (value * annual_interest);
        printf("Total accumulated value is $%f\n", value); }

        else /* when x = 1 */
        value = (acc_amount + (acc_amount * annual_interest));
        { printf("Total accumulated value is $%f\n", value); }
        x = x + 1;
  }
      }

[Salem]

First, you need a better approach to indentation.

/* File: account.c
*     * Date: February 2, 2010 */

/* This program calculates the accumulated value of a given initial investment and annual interest, given the options of either annual, monthly, or daily
* compounding */

#include <stdio.h>

/* Function declaration */
float calc_acc_amt(int x, float acc_amount, float annual_interest, int y);

main()
{
    /* Variable declarations */
    float initial;              /* Input initial value of investment */
    float interest;             /* Input annual interest */
    float input;                /* User input of initial value and annual interest */
    int type;                   /* Input type of compounding */
    int start = 1;              /* Used for start of loop in function */
    float acc_amt;              /* Accumulated amount of investment invoked by function */
    float monthly_interest;     /* Modified interest due to chosen input of monthly compounding */
    float daily_interest;       /* Modified interest due to chosen input of daily compounding */
    int length;                 /* Length of compounding */

    /* Program intro */
    printf
        ("This program will calculate the accumulated value of your investment at an annual, monthly, or daily compounding\n");

    /* Obtain input from user */
    printf("Please enter the following data, seperated by spaces.\n");
    printf("Initial value, annual interest: ");
    input = scanf("%f %f", &initial, &interest);

    printf("Type of compounding: (1) annually, (2) monthly, (3) daily: ");
    input = scanf("%d", &type);

    printf("Length of compounding: ");
    scanf("%d", &length);

    while (input != EOF) {      /* Initialize loop */
        if (type = 1) {         /* Invoke function */
            acc_amt = calc_acc_amt(start, initial, interest, length);

        }
        if (type = 2) {
            monthly_interest = (interest) / (12);
            acc_amt =
                calc_acc_amt(start, initial, monthly_interest, length);
        }
        if (type = 3) {
            daily_interest = (interest) / (365);
            acc_amt = calc_acc_amt(start, initial, daily_interest, length);
        }
        if (type != 1 || type != 2 || type != 3) {
            printf("Please indicate type of compound.");
            break;
        }

        /* Update loop */
        printf("Initial value, annual interest: ");
        input = scanf("%f %f", &initial, &interest);

        printf
            ("Type of compounding: (1) annually, (2) monthly, (3) daily: ");
        input = scanf("%d", &type);
    }

}                               /* End main */

/* Function */

float calc_acc_amt(int x, float acc_amount, float annual_interest, int y)
{
    float value;
    while (x <= y) {
        printf("%d: ", x);
        if (x != 1) {           /* when x is not equal to 1 */
            value = value + (value * annual_interest);
            printf("Total accumulated value is $%f\n", value);
        }

        else                    /* when x = 1 */
            value = (acc_amount + (acc_amount * annual_interest));
        {
            printf("Total accumulated value is $%f\n", value);
        }
        x = x + 1;
    }
}

What's happening at line 83 ? Is something meant to be in those braces?

The next step is use a compiler with a good range of diagnostics.

$ gcc -W -Wall -O2 foo.c
foo.c:13: warning: return type defaults to ‘int’
foo.c: In function ‘main’:
foo.c:41: warning: suggest brackets around assignment used as truth value
foo.c:45: warning: suggest brackets around assignment used as truth value
foo.c:50: warning: suggest brackets around assignment used as truth value
foo.c:38: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result
foo.c: In function ‘calc_acc_amt’:
foo.c:89: warning: control reaches end of non-void function
foo.c: In function ‘main’:
foo.c:68: warning: control reaches end of non-void function
foo.c: In function ‘calc_acc_amt’:
foo.c:74: warning: ‘value’ may be used uninitialised in this function

The first few all refer to those if (type = 1) where you should be using if (type =[B]=[/B] 1)

[WaltP]

Your if statements

if (type = 1)
if (type = 2)
if (type = 3)

are setting type to the values 1, 2, 3 and each if is executed because of that. Look up the comparison operators again.