C programming to make multiplication table (1-12) - c

Question

I want to make a program that takes a single integer command line argument (n) and makes n x n multiplication table resembling the 4x4 example below. It should be only 1 through 12, but shouldn't be no smaller or larger. So if there is not enough argument, it should be print a usuage: Usage: program <n> \n or if it is out of range then it should be print: n out of range (1-12)\n and exit.
Example:
./program 4
* 1 2 3 4
+----------------
1| 1 2 3 4
2| 2 4 6 8
3| 3 6 9 12
4| 4 8 12 16
My code I have tried but wasn't success. I have copied the compiled is not what I expected in the below.
#include <stdio.h>
int main(void)
{
int i, j;
printf(" +");
for (i = 1; i < 13; ++i)
{
printf("%#3d ", i);
printf("\n");
}
for (i = 1; i < 64; ++i)
{
printf("-");
printf("\n");
}
for (i = 1; i < 13; ++i)
{
printf("%#2d |", i);
for (j = 1; j < 11; ++j)
{
printf("%#3d ", i * j);
printf("\n");
}
}
return 0;
}
After compile:
gcc version 4.6.3
+ 1
2
3
4
5
6
7
8
9
10
11
12
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
1 | 1
2
3
4
5
6
7
8
9
10
2 | 2
4
6
8
10
12
14
16
18
20
3 | 3
6
9
12
15
18
21
24
27
30
4 | 4
8
12
16
20
24
28
32
36
40
5 | 5
10
15
20
25
30
35
40
45
50
6 | 6
12
18
24
30
36
42
48
54
60
7 | 7
14
21
28
35
42
49
56
63
70
8 | 8
16
24
32
40
48
56
64
72
80
9 | 9
18
27
36
45
54
63
72
81
90
10 | 10
20
30
40
50
60
70
80
90
100
11 | 11
22
33
44
55
66
77
88
99
110
12 | 12
24
36
48
60
72
84
96
108
120
I have been stuck on this for 2 days and trying to figure it out why is it going straight down.. Thank you.

Answer 1

the following code:
corrects the output formatting,
checks if there is a command line parameter,
follows the axiom:
only one statement per line and (at most) one variable declaration per statement.
checks the command line parameter to assure it is numeric and in the range 1...12
limits the scope of each variable
calls puts() where appropriate as printf() is very expensive in CPU cycles
uses appropriate horizontal spacing for readability
and now, the proposed code:
#include <stdio.h>
#include <stdlib.h> // exit(), EXIT_FAILURE
#include <ctype.h> // isdigit()
#define MAX_VALUE 12
#define MIN_VALUE 1
int main( int argc, char *argv[] )
{
if( argc != 2 )
{
fprintf( stderr, "USAGE: %s <maxTableSize: range 1...12>\n", argv[0] );
exit( EXIT_FAILURE );
}
// implied else, user entered a command line parameter
if( !isdigit( argv[1][0] ) )
{
fprintf( stderr, "command line parameter not numeric\n" );
exit( EXIT_FAILURE );
}
// implied else, command line parameter starts with digit
int maxTableSize = atoi( argv[1] );
if( MIN_VALUE > maxTableSize || maxTableSize > MAX_VALUE )
{
fprintf( stderr, "command line parameter not in valid range ( 1...12 )\n");
exit( EXIT_FAILURE );
}
// implied else, command line parameter contains valid value
printf(" + ");
for ( int i = 1; i <= maxTableSize; ++i )
{
printf("%4d ", i);
}
puts("");
for ( int i = 1; i < 5+(maxTableSize*5); ++i )
{
printf( "-" );
}
puts("");
for ( int i = 1; i <= maxTableSize; ++i )
{
printf( "%2d |", i );
for ( int j = 1; j <= maxTableSize; ++j )
{
printf( "%4d ", i * j );
}
puts("");
}
return 0;
}
the following demonstrates the various conditions of running the program. (where untitled is the name of the program.)
./untitled
USAGE: ./untitled <maxTableSize: range 1...12>
./untitled a
command line parameter not numeric
./untitled 0
command line parameter not in valid range ( 1...12 )
./untitled 13
command line parameter not in valid range ( 1...12 )
./untitled 1
+ 1
--------
1 | 1
./untitled 2
+ 1 2
------------
1 | 1 2
2 | 2 4
.....
./untitled 12
+ 1 2 3 4 5 6 7 8 9 10 11 12
----------------------------------------------------------------
1 | 1 2 3 4 5 6 7 8 9 10 11 12
2 | 2 4 6 8 10 12 14 16 18 20 22 24
3 | 3 6 9 12 15 18 21 24 27 30 33 36
4 | 4 8 12 16 20 24 28 32 36 40 44 48
5 | 5 10 15 20 25 30 35 40 45 50 55 60
6 | 6 12 18 24 30 36 42 48 54 60 66 72
7 | 7 14 21 28 35 42 49 56 63 70 77 84
8 | 8 16 24 32 40 48 56 64 72 80 88 96
9 | 9 18 27 36 45 54 63 72 81 90 99 108
10 | 10 20 30 40 50 60 70 80 90 100 110 120
11 | 11 22 33 44 55 66 77 88 99 110 121 132
12 | 12 24 36 48 60 72 84 96 108 120 132 144

Answer 2

In your code, you are making 2 mistakes.
You are adding the printf ("\n") inside the for loop. This should be outside the for loop in case of single loop. In case of nested loop, the new line should be after each internal for loop.
You are using %#3d in printf. The # should be removed.
Other than that, after making few changes in printf alignment, the updated code is below
#include <stdio.h>
int main(void)
{
int i, j;
printf(" +");
for (i = 1; i < 13; ++i)
{
printf("%4d ", i);
}
printf("\n");
for (i = 1; i < 64; ++i)
{
printf("-");
}
printf("\n");
for (i = 1; i < 13; ++i)
{
printf("%2d |", i);
for (j = 1; j < 13; ++j)
{
printf("%4d ", i * j);
}
printf("\n");
}
return 0;
}
Output is as below
+ 1 2 3 4 5 6 7 8 9 10 11 12
---------------------------------------------------------------
1 | 1 2 3 4 5 6 7 8 9 10 11 12
2 | 2 4 6 8 10 12 14 16 18 20 22 24
3 | 3 6 9 12 15 18 21 24 27 30 33 36
4 | 4 8 12 16 20 24 28 32 36 40 44 48
5 | 5 10 15 20 25 30 35 40 45 50 55 60
6 | 6 12 18 24 30 36 42 48 54 60 66 72
7 | 7 14 21 28 35 42 49 56 63 70 77 84
8 | 8 16 24 32 40 48 56 64 72 80 88 96
9 | 9 18 27 36 45 54 63 72 81 90 99 108
10 | 10 20 30 40 50 60 70 80 90 100 110 120
11 | 11 22 33 44 55 66 77 88 99 110 121 132
12 | 12 24 36 48 60 72 84 96 108 120 132 144