Syntax error in my C code? [closed] - c

Question

Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers.
This question was caused by a typo or a problem that can no longer be reproduced. While similar questions may be on-topic here, this one was resolved in a way less likely to help future readers.
Closed 6 years ago.
Improve this question
Ok so basically, I am trying to make a program that will take a KPH of 185 and convert it to MPH all the way to 0 like so. (using prototypes)
Kilometers per hour converted to miles per hour:
Kph Mph
185 115
180 112
175 109
... ...
10 6
5 3
0 0
Unfortunately my conversion is a bit off, can someone heed some information on why that may be?
#include <stdio.h>
// Prototypes
double mph2kph(double); // convert Miles to KM
double kph2mph(double); // convert KM to Miles
int main()
{
int loop = 1;
double kph = 185; // kilometers per hour
double mph = 115; // miles per hour for computation
printf("Kilometers per hour converted to miles per hour: \n");
printf("Kph Mph\n"); // Display Header
while (loop == 1){
printf("%.2d %.2d \n", kph, kph2mph(kph));
break;
}
loop = 0;
}
//Other Functions:
double mph2kph(double x){
return x*1.61;
}
double kph2mph(double x){
return x*1.61;
}
Output =
Kilometers per hour converted to miles per hour:
Kph Mph
40325120 38090656

Answer 1

You are using %d to show your final result, which is used for int variables. In your case, as you are using double variables, you should go for %f or %lf.
printf("%.2lf %.2lf \n", kph, kph2mph(kph));
Also, your kilometers per hour to miles per hour conversion function is wrong. You should divide and not multiply.
double kph2mph(double x){
return x/1.61;
}
Testing your code with those corrections leads to correct results:
Kilometers per hour converted to miles per hour:
Kph Mph
185.00 114.91

Answer 2

I have made some changes to your program to give your desired output. Some errors in your program are already identified by some other users. Compare this with yours and try to learn. Best of luck!
#include <stdio.h>
// Prototypes
double mph2kph(double); // convert Miles to KM
double kph2mph(double); // convert KM to Miles
int main()
{
int loop = 1;
int kph = 185; // kilometers per hour
double mph = 115; // miles per hour for computation
printf("Kilometers per hour converted to miles per hour: \n");
printf("Kph Mph\n"); // Display Header
while (kph != -5){
printf("%d %.2lf \n", kph, kph2mph(kph));
getchar();
kph = kph - 5;
}
}
//Other Functions:
double mph2kph(double x){
return x*1.61;
}
double kph2mph(double x){
return x/1.61;
}