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#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
//Function Prototypes ***************************
bool openFile(fstream &inFile);
void validateFileData(fstream &inFile, int& numRows, int& numCols);
double getGrayValue(fstream &inFile, int numRows, int numCols);
/************************************************
***************************** M A I N **********
************************************************/
int main() {
//Var Dictionary ****************************
int numRows, numCols; //size of our ppm image
bool isGoodFile; //tells if file opened OK
double grayValue; //grayscale: avg of all pixels in img
fstream inFile; //file holding ppm image
//1.0 Init
isGoodFile = openFile(inFile);
//2.0 Process File **************************
if (isGoodFile) {//we have a file to process
validateFileData(inFile, numRows, numCols);
if ((numRows>0) && (numCols>0)) {//we have proper PPM file
grayValue = getGrayValue(inFile, numRows, numCols);
cout << "\nThe average value for this image is: " << grayValue << endl;
} else //file did not match PPM spec's
cout<<"The file was not in proper ASCII PPM format\n\n";
}//isGoodFile
else //file failed to open properly
cout<<"File failed to open correctly\n";
//3.0 Finish up *****************************
inFile.close(); //must always CLOSE all files we open
cout<<"\n\n\n\t<<< Normal Termination >>>\n\n";
return 0;
}
/************************************************
***************************** openFile **********
************************************************/
bool openFile (fstream &inFile) {
//Receives fstream input file
//Prompts user for path/name & attempts to open file
//Returns T/F if open succeeded or not
//var dictionary
char fileName[80]; //path & name of PPM file
//1.0) Prompt user & get filename
cout<<"\nPlease enter the name of your PPM file: ";
cin.getline(fileName,80);
cout<<"\nFile name is: "<< fileName << endl; //data echo
//2.0) Attempt to open file
inFile.open(fileName);
return (inFile.good()); //true if file OK
}//openFile
/************************************************
***************************** validateFileData **
************************************************/
void validateFileData(fstream &inFile, int& numRows, int& numCols){
//Receives fstream input file (already opened)
//Processes (and verifies) file is ASCII PPM format
//Returns with numCols (width) and numRows (height) of image
// and the file pointer at the first pixel of file
// If file is not in PPM format, will print errMsg
// and return -1 for numRows/numCols.
//var dictionary
int width, height, maxColor; //PPM characteristics
bool isGoodPPM = true; //flag for our tests
char myLine[80]; //lines of PPM file (text)
//1.0) Test 1st line: "P3"
cout<<"\nData echo of file input:\n";
inFile.getline(myLine, 80); //grab whole 1st line
cout<<myLine<<endl; //echo it back to human
if ((myLine[0]!='P') || (myLine[1]!='3')) //test it
isGoodPPM = false; //we have bad file
//2.0 Test 2nd line (if needed): "# any old comment"
if (isGoodPPM) {//keep testing ONLY if file still alive
inFile.getline(myLine,80); //grab whole 2nd line
cout<<myLine<<endl; //echo it back to human
if (myLine[0]!='#') //test for comment
isGoodPPM = false; //bad file
}
//3.0 Test 3rd & 4th lines: "<width> <height> <255>
if (isGoodPPM) {
inFile >> width >> height >> maxColor; //grab 3 integers
cout << width << " " << height << endl //echo back
<< maxColor << endl;
//test our numbers
if ((width<=0) || (height<=0) || (maxColor!=255))
isGoodPPM = false; //bad file
}
//4.0 Return results
if (isGoodPPM) { //file passed inspection
numCols = width; numRows = height;
} else {
numCols = numRows = -1; //bad file
}
}//validateFileData
/************************************************
***************************** getAvgPixel *******
************************************************/
double getGrayValue(fstream &inFile, int numRows, int numCols){
//Receives fstream input file, with pointer at first pixel value
// and the numRows (height) and numCols (width) of image
//Reads all pixels (RGB Values)
//Returns the average (double) of all the pixels (grayScale value)
double average = 0.0; //variable to return the average
const int MAXROW = numRows;//variable for max amount of rows, added one so i could use it in a loop better
const int MAXCOL = numCols;//variable for max amount of rows, added one so i could use it in a loop better
char myLine[80];//set up array to store the values in
int temp=0;//variable to temporarily store numbers in
int adding=0;//variable to store the added numbers in
int total=0;//variable to store the total amount of numbers in
int column=0;//variable to store column position
int row=0;//variable to store column position
const int MYLINEMAX =81;
inFile.getline(myLine, 80);
while((column<MAXCOL) && (row<MAXROW)){//set up a loop for the row
for(int i=0;i<MYLINEMAX;i++){
temp=adding;
adding=temp+myLine[i];
total++;
}
average=adding/total;
}
return average;
}//getGrayValue
IM如何做的最後一部分數學極其混亂，檢查工作正常，但我似乎無法做數學題，即使我啓動'average'as 0在我的命令提示符中沒有打印出任何內容獲取灰度顏色的平均從ASCII圖像