C++ with Magic Square

[008325]

i have a question about the magic square

for example , 3 * 3 magic square = 1,2,3,4,5,6,7,8,9

and user input to string array

1 2 3
4 5 6
7 8 9

how can i check the string array value are unique and contain 1 to 9?

[aks44]

WRT the "1 to 9" validation, it's quite easy to test the strings / characters and see if they match the allowed character range.

Concerning their uniqueness, std::vector<bool>, std::set<int> (which would be overkill though) or even a custom bitfield could all do the trick, since your set of possible values is very small.

[gnusci]

Here one small code that can help you to find the solution:




// numbers.c
#include <stdio.h>

int count_number( char* s, char num ){
int count = 0;
while( *s ){
if((char)*s == num){
count++;
}
s++;
}
return count;
}

// 0-9
char NUM[10] = {'0','1','2','3','4','5','6','7','8','9'};

int main(void){

int i, n;
char magic[10] = {'5','1','3','3','2','5','1','7','1','9'};

for(i=0; i<10; i++){
n = count_number(magic,NUM[i]);
printf("the number [%c] is %i times\n",NUM[i],n);
}
return 0;
}



> gcc number.c -o number
> ./number

[CptPicard]

Too complex. :) All he needs to do is to convert into ints or chars (in the byte sense) when reading input, and just have a bool[9] as suggested to keep track of whether a number has been seen already. Each element should be true in the end, and just once .. trying to set true one more time should be an error. It's a few lines.

Btw, this has the dinstinct whiff of homework to it... :)

[aks44]

Btw, this has the dinstinct whiff of homework to it... :)

That's the very reason why I kept my answer quite vague, I was waiting for more info from the OP. ;)