Getting multiple variables from a read in line - c

Question

I am having trouble getting multiple number vars from a read in line. For a single value I can do strtol(), but how can I get the float and long values of a sentence that is similar to as follows.
Please aim 3.567 degrees at a height of 5 meters.
I tried doing two different calls to my buffer sentence, however it got neither of my values. I have no issues with get single values, but with to, I get 0.000 from my strtof call and 0 from mmy strtol call.

Answer 1

Assuming that the input always starts with the string "Please aim ", followed by a floating-point number, followed by the string " degrees at a height of ", followed by an integer, followed by the string " meters.", then you can use the functions strtof and strtol, but you must skip the strings first, for example like this:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main( void )
{
char *line = "Please aim 3.567 degrees at a height of 5 meters.";
char *part1 = "Please aim ";
char *part2 = " degrees at a height of ";
char *part3 = " meters.";
float degrees;
long height;
size_t part1_len = strlen( part1 );
size_t part2_len = strlen( part2 );
size_t part3_len = strlen( part3 );
//make p point to start of line
char *p = line;
char *q;
//verify that the line starts with part1 and skip it
if ( strncmp( p, part1, part1_len ) != 0 )
{
fprintf( stderr, "Unable to find part1!\n" );
exit( EXIT_FAILURE );
}
p += part1_len;
//attempt to convert degrees value and skip it
degrees = strtof( p, &q );
if ( p == q )
{
fprintf( stderr, "Error converting degrees!\n" );
exit( EXIT_FAILURE );
}
p = q;
//verify that the line continues with part2 and skip it
if ( strncmp( p, part2, part2_len ) != 0 )
{
fprintf( stderr, "Unable to find part2!\n" );
exit( EXIT_FAILURE );
}
p += part2_len;
//attempt to convert height value and skip it
height = strtol( p, &q, 10 );
if ( p == q )
{
fprintf( stderr, "Error converting height!\n" );
exit( EXIT_FAILURE );
}
p = q;
//verify that the line continues with part3 and skip it
if ( strncmp( p, part3, part3_len ) != 0 )
{
fprintf( stderr, "Unable to find part3!\n" );
exit( EXIT_FAILURE );
}
p += part3_len;
//verify that we have reached the end of the string
if ( *p != '\0' )
{
fprintf( stderr, "Unexpected character encountered!\n" );
exit( EXIT_FAILURE );
}
//print the results
printf(
"Results:\n"
"Degrees: %f\n"
"Height: %ld\n",
degrees, height
);
}
This program has the following output:
Results:
Degrees: 3.567000
Height: 5