this might be difficult to explain. I am working on a program that takes in a file with numbers in it. the first two numbers are the dimensions of a matrix rows and then columns. the rest of the numbers are the elements of the matrix. what I am having trouble with is that after I created a function to read in a number in a give c style string, the program stops doing anything. It compiles and runs but nothing is ever done, not even printing the first line after main.
proj2.c
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
float readNum(char* buffer, int *pos);
int main(){
char buffer[512];
printf("Enter File Name: ");
//char* fileName = fgets(buffer, sizeof(buffer), stdin);
FILE* file = fopen("matrix.txt", "r");
if(file == NULL){
printf("ERROR COULD NOT OPEN FILE\n");
exit(1);
}
int row = 0;
int col = 0;
int rowcheck = 0;
int colcheck = 0;
int matrixcheck = 0;
while(!feof(file)){
printf("HELLO");
if(fgets(buffer,sizeof(buffer),file) != NULL){
//position of current character
int pos = 0;
//current character
char current;
//loop to determine the dimensions of the matrix
if(colcheck == 0 && rowcheck == 0){
while(colcheck == 0 || rowcheck == 0){
//set current character
current = buffer[pos];
//determine if current character is a number and that the nex character is a space
//for single digit row dimensions
if(current >= '0' && current <= '9' && buffer[pos+1] == ' ' && rowcheck == 0){
row += current - '0';
rowcheck = 1;
}
//if not single digit row dimension add the current character times 10
//and repeat loop to obtain the second digit
else if (buffer[pos+1] >= '0' && buffer[pos+1] <= '9' && rowcheck == 0){
row += (current - '0') * 10;
}
//for columns check if current character is a number and if the next character is space or newline
//and that row has already been checked
else if(current >= '0' && current <= '9' && (buffer[pos+1] == ' ' || buffer[pos+1] == 10) && rowcheck == 1){
col += current - '0';
colcheck = 1;
}
//final check for if columns is double digit so check if next char is a number and that current char is
//not a space
else if(buffer[pos] != ' ' && buffer[pos+1] >= '0' && buffer[pos+1] <= '9' && rowcheck == 1){
col += (current - '0' ) * 10;
}
pos++;
printf("rows: %d cols: %d", row,col);
}
}
//condition to ensure columns and rows have been determined
else if(colcheck == 1 && rowcheck == 1){
//loop to find the elements of the matrix
while(matrixcheck == 0){
current = buffer[pos];
if(buffer[pos + 1] != 10){
if((current >= '0' && current <= '9') || current == '-' || current == '.'){
float num = readNum(buffer, &pos);
printf("number: %f", num);
}
}
}
}
}
}
fclose(file);
}
and readNum.c
#include <stdio.h>
#include <math.h>
float readNum(char* buffer,int *pos){
int negative = 1;
int y = 0;
float number = 0;
if(buffer[*pos] == '-'){
negative = -1;
(*pos)++;
}
while(buffer[*pos + y] >= '0' && buffer[*pos + y] <= '9'){
y++;
}
for(int z = 0; z < y; z++){
number += (buffer[*pos + z] - 48) * pow(10, y - z - 1);
}
*pos += y;
if(buffer[*pos] == '.'){
(*pos)++;
int d = 0;
while(buffer[*pos + d] >= '0' && buffer[*pos + d] <= '9'){
if(buffer[d + *pos] == '.'){
printf("ERROR: multiple decimals in an element");
}
d++;
}
for(int z = 0; z < d; z++){
number += (buffer[z + *pos] - '0') * pow(10, -z - 1);
}
pos += d;
}
return number * negative;
}
commenting out the lines
float num = readNum(buffer, &pos);
printf("number: %f", num);
allows the program to run normally, but uncommenting them it just stops doing anything, in eclipse the console just stays blank running something or other and I terminate it after a bit because nothing is happening, not even the first line is being printed.
this is a sample file that is being read 3 2 56 12 98 25 34.5 45
Thank you in advance
SOLUTION has been found, i'm not sure if everyone understood what exactly is happening in the program. main would not run at all, the first line would not print anything. the solution to this was using fflush(stdout) after the first print statement.
