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/*
* TASK #2 - Summations
*
* GUEST LANGUAGE: THIS IS THE C VERSION OF ch-2.pl.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <assert.h>
#include <unistd.h>
#include <ctype.h>
bool debug=false;
// process_args( argc, argv, &nel, &v );
// Process the -d flag, set nel to the number of
// remaining arguments, check that all those
// remaining arguments are +ve numbers, copy remaining
// args to a new integer dynamic array v.
void process_args( int argc, char **argv, int *nel, int **v )
{
int arg=1;
if( argc>1 && strcmp( argv[arg], "-d" ) == 0 )
{
debug++;
arg++;
}
*nel = argc-arg;
if( *nel < 2 )
{
fprintf( stderr,
"Usage: summations [-d] list of +ve numbers\n" );
exit(1);
}
int lastpos = argc-1;
// elements are in argv[arg..lastpos], copy them to new int v[] array
// allocate the array
*v = malloc( *nel * sizeof(int) );
assert( *v != NULL );
if( debug )
{
printf( "debug: arg=%d, lastpos=%d, nel=%d\n",
arg, lastpos, *nel );
}
// check that all remaining arguments are +ve integers,
// and then copy them to v[]
for( int i=arg; i<=lastpos; i++ )
{
if( ! isdigit(argv[i][0]) )
{
fprintf( stderr,
"sum-bitwise-pairs: arg %d (%s) is not a +ve number\n",
i, argv[i] );
exit(1);
}
(*v)[i-arg] = atoi( argv[i] );
//printf( "debug: v[%d] = %d\n", i-arg, (*v)[i-arg] );
}
}
int main( int argc, char **argv )
{
int nel;
int *v;
process_args( argc, argv, &nel, &v );
int r = 1;
if( debug )
{
printf( "row %d:", r );
for( int i=0; i<nel; i++ )
{
printf( " %d", v[i] );
}
putchar( '\n' );
}
while( nel > 1 )
{
// shift v array down
for( int i=0; i<nel; i++ )
{
v[i] = v[i+1];
}
v[nel-1] = -1;
nel--;
for( int pos = 1; pos<nel; pos++ )
{
v[pos] += v[pos-1];
}
r++;
if( debug )
{
printf( "row %d:", r );
for( int i=0; i<nel; i++ )
{
printf( " %d", v[i] );
}
putchar( '\n' );
}
}
printf( "%d\n", v[0] );
free( v );
}
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