Thread: Trying to write a program that will display a fuel economy conversion table

So we have to write a C Program that will display a fuel economy conversion table as follows:

Litres Miles
per per
100 KM Gallon
4.0 70.6
4.1 68.9
4.2 67.3
4.3 65.7
4.4 64.2
4.5 62.8
4.6 61.4
4.7 60.1
4.8 58.9
4.9 57.6
5.0 56.5
5.1 55.4
5.2 54.3
5.3 53.3
5.4 52.3
5.5 51.4
5.6 50.4
5.7 49.6
5.8 48.7
5.9 47.9
6.0 47.1
6.1 46.3
6.2 45.6
6.3 44.8
6.4 44.1
6.5 43.5
6.6 42.8
6.7 42.2
6.8 41.5
6.9 40.9
7.0 40.4
7.1 39.8
7.2 39.2
7.3 38.7
7.4 38.2
7.5 37.7
7.6 37.2
7.7 36.7
7.8 36.2
7.9 35.8
8.0 35.3



And this is my code that will NOT compile in any IDE that I use:

Code:

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


float imoerialGallonperlitres (float litres) {


    float gallon;
    gallon=litres*0.219969;
    return gallon;
}
float MilesperImperialGallon (float gallon) {


    float miles;
    miles=100/gallon*0.621371;
    return miles;
}
int main(void) {


    float litres=4.0;
    float miles;
    float imperialgallon;
    printf("Litres Miles\n");
    printf("per    per\n");
    printf("100 KM Gallon\n");
    printf("");
    printf("");
    printf("");


    for(int i=0; i<41;i++){
    imperialgallon=imoerialGallonperlitres (litres) ;
    miles=MilesperImperialGallon (imperialgallon) ;
    printf("%.1f  %.1f\n", litres, miles);
    litres=litres+0.1;
    }
    return EXIT_SUCCESS;
}

Could someone please tell me what I'm doing wrong? My friends can't seem to figure it out either. I have an assignmentdue tonight and this is getting very frustrating.

Code:

/*
main.c|33|error: 'for' loop initial declarations are only allowed in C99 mode
*/

Code:

for(int i=0; i<41;i++)

Are you compiling with respect to C99?

If not, then declare 'i' outside of the "for()" loop.

Your code is correct (in C99 and above). What for compilers are using your IDE's and on which OS?
I have compiled with GCC on Debian/GNU Linux. Here is the output:

Code:

$ gcc -Wall -o foo foo.c 
foo.c: In function ‘main’:
foo.c:28:2: warning: zero-length gnu_printf format string [-Wformat-zero-length]
foo.c:29:2: warning: zero-length gnu_printf format string [-Wformat-zero-length]
foo.c:30:2: warning: zero-length gnu_printf format string [-Wformat-zero-length]
foo.c:32:2: error: ‘for’ loop initial declarations are only allowed in C99 mode
foo.c:32:2: note: use option -std=c99 or -std=gnu99 to compile your code

The 3 warnings (line 28-30) are from printf-function with empty string.
The error came from declaration of variable 'i' inside the for-statment.
This is allowed since C99. I think you work on Windows.

I can compile the code without problems like …

Code:

gcc -std=c99 -Wall -o foo foo.c
gcc -std=c11 -Wall -o foo foo.c

… and it works as expected.

You're right! I tried both on the school linux computers and on my mac and it didn't work. I declared "i" outside the for statement and it's now working on both. Thanks a bunch!