Question

1. Write a text file contains a square matrix of integer numbers. The file contains an integer number indicating the identical number of rows and columns followed by the data itself (that number cannot be larger than 100). For example, a file containing a 3x3 matrix would contain 3 followed by 9 other integer numbers. The program will call one function to determine if all the numbers on the main diagonal are the same.




2. The function is called checkdiag (int checkdiag (int matrix[][100], int size)) that will return 1 if all the numbers on the main diagonal are the same and 0 otherwise.




3. Your program will read the array from the file, check the diagonal and print a report containing the size and the status of the diagonal. A typical report would look like The matrix is 3x3 and all the numbers on the main diagonal are the same.

Answer 1

#include <stdio.h>

int checkdiag (int matrix[][100], int size);

int main(){

   int matrix[100][100];

   int size;

   char filename[30];

   FILE *fp;

   int i,j;

   

   printf("Enter input filename: ");

   scanf("%s", filename);

   

   fp = fopen(filename, "r");

   if(fp == NULL){

      printf("ERROR: could not open file %s\n", filename);

      return 1;

   }

   

   fscanf(fp, "%d", &size);

   for(i = 0; i < size; i++){

      for(j = 0; j < size; j++){

         fscanf(fp, "%d", &matrix[i][j]);

      }

   }

   

   if(checkdiag(matrix, size))

      printf("The matrix is %dx%d and all the numbers on the main diagonal are the same.\n", size, size);

   else

      printf("The matrix is %dx%d and all the numbers on the main diagonal are NOT the same.\n", size, size);

   return 0;

}

int checkdiag (int matrix[][100], int size){

   int i;

   for(i = 1; i < size; i++){

      if(matrix[i][i] != matrix[i-1][i-1])

         return 0;

   }

   return 1;

}