Can't find the right max Value in my Array loop - c++

Question

So my professor gave us this project to read a text file and find the max value, min value, sum. But for some reason when I write the for loop to find the max value it returns a number thats not even in the text file... and I don't know what i did wrong. I'll attach my code and also the output. Thank you
int main () {
ifstream myFile;
char myArray[210];
int i;
int maxVal;
int j;
int minValue;
double myAverage;
myFile.open("Lab #5A Data File.Txt", ios::in | ios::out);
if (myFile.is_open()) {
cout << "The file is open." << endl;
myFile >> noskipws;
while (!myFile.eof()){
for (i=0; i<210; ++i) {
myFile >> myArray[i];
cout << myArray[i];
}
myFile >>myArray[i];
}
maxVal=myArray[0];
for (j=0; j< 210; j++)
if (myArray[j] > maxVal){
maxVal=myArray[j];
}
What i get when I run the code :
The file is open.
346 130 982 90 656 117 595
415 948 126 4 558 571 87
42 360 412 721 463 47 119
441 190 985 214 509 2 571
77 81 681 651 995 93 74
310 9 995 561 92 14 288
466 664 892 8 766 34 639
151 64 98 813 67 834 369
The max value is: 51 <--- I have no idea where this number came from...

Answer 1

The 51 is coming from the line:
maxVal=myArray[0];
In your loop to try to find the biggest element you have:
for (j=0; j< 210; j++)
if (myArray[j] > maxVal){
myArray[i]=maxVal;
}
}
However this will assign maxVal to myArray[i] which is not what you want. First of all you need to be assigning myArray[j], not myArray[i], and secondly you need to assign maxVal to the bigger value. As it is maxVal=myArray[0]; is the only time you assign anything to maxVal, which is why it is 51 (The ASCII value of the character 3, which is the first character you read). You need to do something along the lines of:
if (myArray[j] > maxVal){
maxVal = myArray[j];
}
I believe you wanted myArray to be an int[]. Also a better way of doing this is instead of having two for loops and looping until EOF, loop while myFile >> myArray[i]:
int myArray[210];
int i = 0;
//...
while (myFile >> myArray[i]) {
cout << myArray[i] << " ";
if (myArray[i] > maxVal) {
maxVal = myArray[i];
}
i++;
}
Which for the input file:
346 130 982 90 656 117 595
415 948 126 4 558 571 87 42
360 412 721 463 47 119 441
190 985 214 509 2 571 77 81
681 651 995 93 74 310 9 995
561 92 14 288 466 664 892 8
766 34 639 151 64 98 813 67 834 369
Returns:
995

Answer 2

To achieve what you want, you cannot do a comparison like this
if (myArray[j] > maxVal){
because myArray[j] is a char (definitely not holding the integers you are interested in) and maxVal is an int. This is also the reason you see a 51 - when you try to store an integer into your char, you essentially only read 8 bits from the stream (which results in some value between 0 and 254 which is basically just some 8-bit block from your input stream).
You definitely want something like
char myArray[32][210];
to be able to read your full integers from the stream into one of these 210 char* slots.
Then, when comparing (and assigning to maxValue), you need to convert the textual int value to a numeric value, e.g., using atoi().