Styjun

Creating a code that prints out Body Mass Index

printf("What is your height in inches?n");
scanf("%d", height);

printf("What is your weight in pounds?n");
scanf("%d", weight);

I have height and weight as initialized as int height, int weight, but the program is not letting me run it because it says the format is type int* on both scanf lines. What am I doing wrong to get this program to run?

scanf requires the format (your "%d") and also a memory address of the variable where it should put the value that was read. height and weight are int, not the memory address of an int (this is what int * type 'says': a pointer to a memory address of an int). You should use the operator & to pass the memory address to scanf.

Your code should be:

printf("What is your height in inches?n");
scanf("%d", &height);

printf("What is your weight in pounds?n");
scanf("%d", &weight);

Update: As The Paramagnetic Croissant pointed out, reference is not the correct term.So I changed it to memory address.

taking into account what the other users have said, try something like this;

int height; <---- declaring your variables
int weight;
float bmi; <---- bmi is a float because it has decimal values

printf("What is your height in inches?n");
scanf("%d", &height); <----- don't forget to have '&' before variable you are storing the value in

printf("What is your weight in pounds?n");
scanf("%d", &weight);


bmi = (weight / pow(height, 2)) * 703; <---- the math for calculating BMI
printf("The BMI is %fn", bmi);

(for this you will need to include the math.h library.)

scanf reads characters from the standard input, interprets them according to the format specifiers here "%d" for integers and stores them in corresponding arguments.

To store them you must specify &variable_name, it will specify the address location where the input should be stored.

Your scanf statement should be:

//For storing value of height
scanf(" %d", &height);
//For storing value of weight
scanf(" %d", &weight);

Like others have said, it's because when you have a value that is a primitive (like an int) that is being read with scanf you have to pass the memory address to that primitive value. However, just to add something that has not been mentioned yet, the same is not true for strings.

Example 1. Using with a primitive value

#include <stdio.h>

int main()

 int primitiveInteger; // integer (i.e. no decimals allowed)
 scanf("%i", &primitiveInteger); // notice the address of operator getting the address of the primitiveInteger variable by prepending the variable name with the & (address of) operator.
 printf("Your integer is %i", primitiveInteger); simply printing it out here to the stdout stream (most likely your terminal.)

Example 2. Not using a primitive value

#include <stdio.h>

int main()

 char *nonPrimitiveString; // initialize a string variable which is NOT a primitive in C
 scanf("%s", nonPrimitiveString); // notice there is no address of operator here
 printf("%sn", nonPrimitiveString); // prints string