/* Scott Johnson
   matrix store and recall (file) using functions, aditional function for matrix addition
   08/04/2007
*/
#include<stdio.h>

struct matrix{
       int cols;
       int rows;
       float arr[16][16];
};

void getMatrix(struct matrix *m);
void showMatrix(struct matrix *m);
int saveMatrix(struct matrix *m, char *n);
int loadMatrix(struct matrix *m, char *n);
int sum(struct matrix *m1,struct matrix *m2,struct matrix *m3);
int product(struct matrix *m1,struct matrix *m2,struct matrix *m3);

main(){
       struct matrix m1,m2,m3;
       int i;
       /* read first matrix. save in mat1.txt */  
       printf("matrix 1\n");
       getMatrix(&m1);
       i=saveMatrix(&m1,"mat1.txt");
       /* read second matrix. save in mat2.txt */  
       printf("matrix 2\n");
       getMatrix(&m1);
       i=saveMatrix(&m1,"mat2.txt");
       /* load mat1.txt into m1, mat2.txt into m2 */  
       i=loadMatrix(&m1,"mat1.txt");
       i=loadMatrix(&m2,"mat2.txt");
       /*
        add m1 to m2, result in m3.
         display result if sizes compatible
          otherwise give error message
          */
        i=sum(&m1,&m2,&m3);
        if(i!=0){
                printf("Matrix sizes incompatible\n");
        }else{    
              printf("sum\n");
              showMatrix(&m3);
        }  
        i=product(&m1,&m2,&m3);
        if(i!=0){
                printf("Matrix sizes incompatible\n");
        }else{
                printf("product\n");
                showMatrix(&m3);  
        }
        i=product(&m2,&m1,&m3);
        if(i!=0)
                printf("Matrix sizes incompatible\n");
        else
                showMatrix(&m3);  

}


void getMatrix(struct matrix *m){
                      int row,i;
                      printf("enter the number of columns ");
                      scanf("%d",&(*m).cols);
                      printf("enter the number of rows ");
                      scanf("%d",&(*m).rows);
                      printf("number of columns %d\n",(*m).cols);
                      printf("number of rows %d\n",(*m).rows);
                      for(row = 0; row<(*m).rows;row++){
                      printf("enter %d values of row %d ",(*m).cols,row+1);
                                    for(i = 0; i<(*m).cols;i++){
                                    scanf("%f",&(*m).arr[i][row]);
                                    }
                      }
}
void showMatrix(struct matrix *m){
                       int row,i;
                       for(row = 0; row<(*m).rows;row++){
                               for(i = 0; i<(*m).cols;i++){
                               printf("%f ",(*m).arr[i][row]);
                               }
                       printf("\n");
                       }
}

int saveMatrix(struct matrix *m, char *n){
                      int row,i;
                      FILE *store;
                      store = fopen(n,"w");
                      fprintf(store,"%d\n",(*m).cols);
                      fprintf(store,"%d\n",(*m).rows);
                                    for(row = 0; row<(*m).rows;row++){
                                            for(i = 0; i<(*m).cols;i++){
                                            fprintf(store,"%f ",(*m).arr[i][row]);
                                            }
                                    fprintf(store,"\n");
                                    }
                      fclose(store);
                      return 0;
}    

int loadMatrix(struct matrix *m, char *n){
                      int row,i;
                      FILE *store;
                      store = fopen(n,"r");
                      if (store == (NULL)) {
                               return -1;
                      }else{
                      fscanf(store,"%d\n",&(*m).cols);
                      fscanf(store,"%d\n",&(*m).rows);
                                    for(row = 0; row<(*m).rows;row++){
                                            for(i = 0; i<(*m).cols;i++){
                                            fscanf(store,"%f ",&(*m).arr[i][row]);
                                            }
                                    fscanf(store,"\n");
                                    }
                      }
                      fclose(store);
                      return 0;
}

int sum(struct matrix *m1,struct matrix *m2,struct matrix *m3){
                      int i,row;
                      if ((*m1).rows != (*m2).rows || (*m1).cols != (*m2).cols){
                                     return -1;
                      } else {
                              (*m3).cols = (*m1).cols;
                              (*m3).rows = (*m1).rows;
                              for(row = 0; row<(*m1).rows;row++){
                                              for(i = 0; i<(*m1).cols;i++){
                                                    (*m3).arr[i][row] = ((*m1).arr[i][row]+(*m2).arr[i][row]);
                                              }
                              }
                      return 0;
                      }
}

int product(struct matrix *m1,struct matrix *m2,struct matrix *m3){
                      int i,row,col;
                      float temp=0;
                      if((*m1).cols != (*m2).rows){
                                    return -1;
                      } else {
                              (*m3).cols = (*m2).cols;
                              (*m3).rows = (*m1).rows;
                              for(col=0, col<(*m2).cols, col++){
                                    for(row=0,row<(*m1).rows,row++){
                                                                    for(i=0, i<(*m1).cols, i++) {
                                                                              temp+=(*m1).arr[i][row]*(*m2).arr[cols][i];
                                                                    }
                                    (*m3).arr[row][col] = temp;
                                    }
                              }
                              return 0; 
                      }
}