Thread: error: syntax error before printf

Hi. I have just learnt C programming and I don;t know what's wrong with the printf("Your BMI is %0.2f.\n", BMI);below. Is there anyone can check it for me please?

Code:

/* Demonstates variables and constants*/
#include <stdio.h>


/*Declare the need variable*/
float BMI;
int height_in_meters, weight_in_killograms;


int main()
{


  /* Input data from user*/


  printf("How tall are you in meters:");
  scanf("d%", &height_in_meters);
  printf("Please enter your weight in killograms:");
  scanf("d%", &weight_in_killograms);
  
  /* Perform conversions*/
  
  BMI = (weight_in_killograms)/(height_in_meters)^2
  
  /* Display result on the screen*/
  
  printf("Your BMI is %0.2f.\n", BMI); 
  
  return 0;
  
}

There is nothing wrong with that line. However, there are several other problems in the code that your compiler should be warning you about. If you haven't already, you should compile with maximum warnings (see your compiler documentation for how to do this).

This is what I got when I compiled your code:

Code:

/*
main.c||In function 'main':|
main.c|17|warning: spurious trailing '%' in format|
main.c|17|warning: too many arguments for format|
main.c|19|warning: spurious trailing '%' in format|
main.c|19|warning: too many arguments for format|
main.c|27|error: expected ';' before 'printf'|
||=== Build finished: 1 errors, 4 warnings ===|
*/

See if you can use these warnings to figure out where your problems are.

Also note that there is no exponent operator in 'C' - so '^' does not do what you think it does (it is the bitwise XOR operator). For smaller powers, you'd be better off just doing repeated multiplication.

I have already correct some of the mistakes here, but I don't know why it still doesn't work.

Code:

/* Demonstates variables and constants*/
#include <stdio.h>


/*Declare the need variable*/
float height_in_meters, weight_in_killograms, BMI;


int main()
{


  /* Input data from user*/


  printf("How tall are you in meters:");
  scanf("d%", &height_in_meters);
  printf("Please enter your weight in killograms:");
  scanf("d%", &weight_in_killograms);
  
  /* Perform conversions*/
  
  BMI = height_in_meters*height_in_meters/weight_in_killograms;
  
  /* Display result on the screen*/
  
  printf("Your BMI is %0.2f.\n", BMI); 
  
  return 0;
  
}

When I try to run the program, there are some of the mistakes like below:

How tall are you in meters:6.1
Please enter your weight in killograms:Your BMI is -1.#J.
Press any key to continue . . .

All right. I am sorry. I have already corrected the mistake here. Thanks for your help.

[code]
/* Demonstates variables and constants*/
#include <stdio.h>


/*Declare the need variable*/
float height_in_meters, weight_in_killograms, BMI;


int main()
{


/* Input data from user*/


printf("How tall are you in meters:");
scanf("%f", &height_in_meters);
printf("Please enter your weight in killograms:");
scanf("%f", &weight_in_killograms);

/* Perform conversions*/

BMI = weight_in_killograms/(height_in_meters*height_in_meters);

/* Display result on the screen*/

printf("Your BMI is %0.2f.\n", BMI);

return 0;
[\code]

You should also stop using global variables, this is very bad practice and since everything is in main() you don't even need the global.

Jim