how to detect a diagonal number of X's - c

Question

i'm an trying to write a program that will call a function win if there is n number of X's or O's in a row. I am have difficulty with the diagonal win that slopes upwards. can any offer any advice on what I should change? Thanks in advance. It calls an infinite loop instead of returning true.
bool left_diag_win(char **board, int num_rows, int num_cols) {
int i;
if (board[0][0] == '*') {
return false;
}
for (i = 1; i < num_rows; ++i) {
if (board[i][i] != board[0][0]) {
return false;
}
}
return true;
}
bool right_diag_win(char **board, int num_rows, int num_cols) {
int i;
if (board[0][num_cols - 1] == '*') {
return false;
}
for (i = 1; i < num_rows; ++i) {
if (board[i][num_cols - i - 1] != board[0][num_cols - 1]) {
return false;
}
}
return true;
}

Answer 1

You code seems correct, but you probably have a problem elsewhere. Here is an example where it behaves as expected:
#include <stdbool.h>
#include <stdio.h>
bool left_diag_win(char **board, int num_rows, int num_cols) {
if (board[0][0] == '*') {
return false;
}
for (int i = 1; i < num_rows; ++i) {
if (board[i][i] != board[0][0]) {
return false;
}
}
return true;
}
bool right_diag_win(char **board, int num_rows, int num_cols) {
if (board[0][num_cols - 1] == '*') {
return false;
}
for (int i = 1; i < num_rows; ++i) {
if (board[i][num_cols - i - 1] != board[0][num_cols - 1]) {
return false;
}
}
return true;
}
int main(void) {
char *matrix1[] = { "X****", "*X***", "**X**", "***X*", "****X" };
char *matrix2[] = { "****X", "***X*", "**X**", "*X***", "X****" };
printf("matrix:\n");
for (int i = 0; i < 5; i++) {
printf("%s\n", matrix1[i]);
}
printf("left-diagonal: %d\n", left_diag_win(matrix1, 5, 5));
printf("right-diagonal: %d\n\n", right_diag_win(matrix1, 5, 5));
printf("matrix:\n");
for (int i = 0; i < 5; i++) {
printf("%s\n", matrix2[i]);
}
printf("left-diagonal: %d\n", left_diag_win(matrix2, 5, 5));
printf("right-diagonal: %d\n\n", right_diag_win(matrix2, 5, 5));
return 0;
}
Output:
matrix:
X****
*X***
**X**
***X*
****X
left-diagonal: 1
right-diagonal: 0
matrix:
****X
***X*
**X**
*X***
X****
left-diagonal: 0
right-diagonal: 1