Angle difference between two bearings: Difference between revisions

</pre>

=={{header|C}}==

This implementation either reads two bearings from the console or a file containing a list of bearings. Usage printed on incorrect invocation.

<lang C>

/*Abhishek Ghosh, 3rd October 2017*/

#include<stdlib.h>

#include<stdio.h>

#include<math.h>

void processFile(char* name){

int i,records;

double diff,b1,b2;

FILE* fp = fopen(name,"r");

fscanf(fp,"%d\n",&records);

for(i=0;i<records;i++){

fscanf(fp,"%lf%lf",&b1,&b2);

diff = fmod(b2-b1,360.0);

printf("\nDifference between b2(%lf) and b1(%lf) is %lf",b2,b1,(diff<-180)?diff+360:((diff>=180)?diff-360:diff));

}

fclose(fp);

}

int main(int argC,char* argV[])

{

double diff;

if(argC < 2)

printf("Usage : %s <bearings separated by a space OR full file name which contains the bearing list>",argV[0]);

else if(argC == 2)

processFile(argV[1]);

else{

diff = fmod(atof(argV[2])-atof(argV[1]),360.0);

printf("Difference between b2(%s) and b1(%s) is %lf",argV[2],argV[1],(diff<-180)?diff+360:((diff>=180)?diff-360:diff));

}

return 0;

}

</lang>

Invocation and output for two bearings :

<pre>

C:\rosettaCode>bearingDiff.exe 29.4803 -88.6381

Difference between b2(-88.6381) and b1(29.4803) is -118.118400

</pre>

File format for bearing list :

<pre>

<Number of records>

<Each record consisting of two bearings separated by a space>

</pre>

Input file :

<pre>

12

20 45

-45 45

-85 90

-95 90

-45 125

-45 145

29.4803 -88.6381

-78.3251 -159.036

-70099.74233810938 29840.67437876723

-165313.6666297357 33693.9894517456

1174.8380510598456 -154146.66490124757

60175.77306795546 42213.07192354373

</pre>

Invocation and output for above bearing list file :

<pre>

C:\rosettaCode>bearingDiff.exe bearingList.txt

Difference between b2(45.000000) and b1(20.000000) is 25.000000

Difference between b2(45.000000) and b1(-45.000000) is 90.000000

Difference between b2(90.000000) and b1(-85.000000) is 175.000000

Difference between b2(90.000000) and b1(-95.000000) is -175.000000

Difference between b2(125.000000) and b1(-45.000000) is 170.000000

Difference between b2(145.000000) and b1(-45.000000) is -170.000000

Difference between b2(-88.638100) and b1(29.480300) is -118.118400

Difference between b2(-159.036000) and b1(-78.325100) is -80.710900

Difference between b2(29840.674379) and b1(-70099.742338) is -139.583283

Difference between b2(33693.989452) and b1(-165313.666630) is -72.343919

Difference between b2(-154146.664901) and b1(1174.838051) is -161.502952

Difference between b2(42213.071924) and b1(60175.773068) is 37.298856