Thread: Print statement won't print

Hi, I'm new to programming and am trying to learn C by doing examples out of the book. My code looks right but my print statement won't show up and neither will the decimal points. Please help. I'm using Dev-C++ as my complier.

Code:

 #include <stdio.h>
 #include <stdlib.h>

/* Print Farenheit-Celsius Table
   for fahr = 0, 20, ... ,300 */
 
   main ()
   {
        float fahr, celsius;
        int lower, upper, step;
        
        lower = 0;        /* Lower limit of temperature table   */
        upper = 300;      /* Upper limit of temperature table   */
        step = 20;        /* Step size                          */
        
        printf("Fahr Celsius \n"); // This line wont print
        fahr = lower;
        while (fahr <= upper) {
              celsius = (5.0/9.0) * (fahr - 32.0);
              printf("%3.0f %6.1f\n", fahr, celsius); // Decimals aren't showing up
              fahr = fahr + step;
              } // end while
                 
        system ("pause"); 


              }// end main

Please post the smallest complete program possible that demonstrates this behavior. In other words, I can't just guess what happens above or below that code segment of yours.

Try including the header needed for the system function stdlib.h

NOTE: My guess is your code is NOT compiling; that is why you see no output.

Tim S.

Does your compiler display any warnings or errors? Post them if yes.

I suggest going back to "Hello World" and finding out what is wrong with your setup or understanding of the IDE and Compiler.

Tim S.

Assuming you're using an IDE, try doing a "Build Clean" or equivalent (the exact label depends on IDE). That will delete all object files and executables. Then rebuild before attempting to run the program.

It is fairly common for some IDE's, when you go through a number of iterations of code, to get confused when a source file does not compile, and then keep launching a previous version of the executable file produced from an old version of your source code.

If you are using some script or makefile for building, then ensure that there is an option to do a cleanup, and use it. Also ensure that the script or makefile checks error status of every command (compilation, linking, etc) and terminates on error. Failure to do that can also get things out of whack between latest code version and the executable file.

If you are compiling by hand (eg doing compilation from a command line) ensure you check each command succeeds before entering the next.



Oh, depending on compiler and IDE: when using floating point, there may be some additional options that need to be set, or libraries included in the build. That is particularly common with unix-based compilers (eg gcc and variants).

P.S. I also guarantee you that your compiler would output some warnings if you compiled with the correct options (e.g. -Wall for gcc, etc.) turned on.

gcc -O0 -g3 -Wall -c -fmessage-length=0 -otest.o ..\test.c
..\test.c:8: warning: return type defaults to 'int'
..\test.c: In function 'main':
..\test.c:27: warning: control reaches end of non-void function

Take the fact that you didn't get warnings as a warning in itself. On a ten-line piece of code it doesn't matter much but still helps, but on a huge program, you could catch any number of problems just by having warnings turned on.

And, please, throw away that ancient C book you're learning from. main() and system("pause")? Really?

This program work for me

In C- programming you must declare every thing before use it in your program.
In your code you should define the system("pause") command before use it.
OK. so, take care of this type of basic but very important topic.

Code:

#include <stdio.h>
#include<conio.h> // i change the header file to conio.h


/* Print Farenheit-Celsius Table
   for fahr = 0, 20, ... ,300 */
 
   main ()
   {
        float fahr, celsius;
        int lower, upper, step;
        
        lower = 0;        /* Lower limit of temperature table   */
        upper = 300;      /* Upper limit of temperature table   */
        step = 20;        /* Step size                          */
        
        printf("Fahr Celsius \n"); // This line wont print
        fahr = lower;
        while (fahr <= upper) {
              celsius = (5.0/9.0) * (fahr - 32.0);
              printf("%3.0f %6.1f\n", fahr, celsius); // Decimals aren't showing up
              fahr = fahr + step;
              } // end while
                 
getch();




              }// end main

abhijitnumber1: note that <conio.h> is a non-standard header, and that getch is not part of the C standard library. So, if you don't really need it, and indeed you do not here, then using it just makes your code less portable without good reason.