readmatrix.c

来自「在MPI上实现的矩阵相乘并行计算的源程序。」· C语言 代码 · 共 48 行

/*read a matrix from a file*/
#include "stdio.h"
#include  "stdlib.h"
#define CHARSIZE sizeof(char)
#define INTSIZE sizeof(int)
int main()
{
 char *filename;
  FILE *fd; /*file pointee to the file */
  int i,j;
  int row,column;
  int value;
  filename=(char *)malloc(CHARSIZE*128);
if (filename==NULL)
{
printf("CANNOT allocate space for filename\n");
exit(0);

}
  printf("Read the content of a file\n");
  printf("Filename:");
  scanf("%s",filename);
  fd=fopen(filename,"r");
 /*open a file for read only and the stream is positioned at the beginning of
the file*/
if(fd==NULL)
 /*error in opening the file*/ 
 {
free(filename);
printf("CANNOT open the file %s coorectly\n",filename);
exit(0); /*exit the system*/ 
}/*if*/
fread(&row,INTSIZE,1,fd);
fread(&column,INTSIZE,1,fd);
printf("Row=%d,Column=%d\n",row,column);
for (i=0;i<row;i++)
 {
 for(j=0;j<column;j++)
   { fread(&value,INTSIZE,1,fd);
     printf("%d ",value);
   }/*for j*/
 printf("\n");
}/*for i*/
fclose(fd);/*close file pointer*/
free(filename);/*free dynamic allocated space*/
return(0);  
}/*main*/