one-file-projects/floyd_warshall.c

#include <stdio.h>

#define N 5

typedef int Mat[N*N];

void matiter(Mat C, int (*reduce)(int old, int ik, int kj)) {
    for(unsigned int k = 0; k < N; k++) {
        for(unsigned int i = 0; i < N; i++) {
            for(unsigned int j = 0; j < N; j++) {
                C[i*N+j] = reduce(C[i*N+j], C[i*N+k], C[k*N+j]);
            }
        }
    }
}

int floyd(int old, int ik, int kj) {
    int new = ik + kj;
    return ( old < new ? old : new );
}

int warshall(int old, int ik, int kj) {
    return (old ? old : ik && kj);
}

int main( int argc, char *argv[] ) {
	Mat C =
    {
        0 , 1 , 0 , 0 , 0,
        0 , 0 , 1 , 0 , 0,
        0 , 0 , 0 , 0 , 0,
        1 , 0 , 0 , 0 , 0,
        0 , 0 , 0 , 1 , 0,
    };

    matiter(C, *warshall);

    for(unsigned int i = 0; i < N; i++) {
        for(unsigned int j = 0; j < N; j++) {
            printf("%5d ", C[i*N+j]);
        }
        printf("\n");
    }

	return 0;
}