如何将此C ++更改为C. [英] How can I change this C++ to C
本文介绍了如何将此C ++更改为C.的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
#include<stdio.h>
#include<string>
#include<iostream>
using namespace std;
const int SIZE = 6;
// parse one equation
void Equation(string line, double coefRow[], double& coefB, string& coefVal){
int len = int(line.length());
bool firstItem = true;
int j=0, m=0;
coefVal = " ";
string eq = "", item="";
for (int i = 0; i < len; i++){
// the case like +x or -x in the start of the line
if (line[i] == '+' || line[i] == '-'){
if (isalpha(line[i + 1])){
coefVal += line[i + 1];
coefRow[j++] = (line[i] == '+') ? 1. : -1.;
i++;
continue;
}
}
// the last coefficient and the coefficient after the sign "="
if (line[i] == '='){
coefRow[j++] = atof(item.c_str()); // the last coefficient
item = "";
for (int l = i + 1; l < len; l++)
item += line[l];
coefB = atof(item.c_str()); // the coefficient after the sign "="
break;
}
if (isalpha(line[i])){
if (firstItem){ // the case like x in the start of the line
firstItem = false;
coefRow[j++] = 1.;
}
else coefRow[j++] = atof(item.c_str()); // the coefficient after the sign "+" or "-"
item = "";
m = 0;
coefVal += line[i];
firstItem = false;
continue;
}
// the case when the current symbol is not letter or sign (digit and decimal)
if (m>8)cerr << "The maximum length of coefficients >8\n";
item += line[i];
m++;
firstItem = false;
}
}
//Recursive function for the determinant calculation
double Determinant(double A[SIZE][SIZE], int size){
double res = 0;
if (size == 2)return A[1][1]; // real matrix size =1
if (size == 3)return A[1][1] * A[2][2] - A[2][1] * A[1][2]; // real matrix size=2
// use the first column and the new matrix with size=size-1
int newSize = size - 1;
double NewA[SIZE][SIZE];
for (int i = 1; i<size;> for (int j = 1; j < newSize; j++){
for (int k = 1; k < newSize; k++)
if (k >= i) NewA[j][k] = A[j+ 1][k + 1];
else NewA[j][k] = A[j + 1][k ];
}
int p = (i % 2) ? 1:-1;
res += p * A[1][i] * Determinant(NewA, newSize); // recursive call function with smaler size
}
return res;
}
// Cramer's rule
void Solve(double A[SIZE][SIZE], double b[SIZE], double sol[SIZE], int size){
double temp[SIZE][SIZE], det;
//call function for the determinant calculation
det = Determinant(A, size);
for (int j = 1; j < size; j++){
//temp = A
// copy A to temp
for (int k = 1; k < size; k++)
for (int l = 1; l < size; l++)
temp[k][l] = A[k][l];
// replace column number j to new values (b)
for (int i = 1; i < size; i++)
temp[i][j] = b[i];
/* print for the program testing
cout << "\ntemp: \n";
for (int k = 1; k < size; k++){
for (int l = 1; l < size; l++)
cout << temp[k][l] << " ";
cout << endl;
}
cout << "det(temp)=" << Determinant(temp, size) << endl;
*/
//the solution of the system
sol[j] = Determinant(temp, size) / det;
}
}
int main(){
// Tests for the program
// string line[] = { "1578x+2345y+8452z=467", "6543x+2348y+9873z=7654", "4230x+6740y+5433z=4546" }; // size = 3
// string line[] = {"78x-45y+52z=7", "43x+48y-73z=54", "30x+40y+33z=46"}; // size = 3
// string line[] = {"50a+37b+c=-44.39", "43a+39b+c=-45.31", "52a+41b+c=-44.96"}; //size = 3
// string line[] = { "a+0b+0c=-44.39", "0a+b+0c=-45.31", "0a+0b+c=-44.96" }; //size = 3
// string line[] = {"2.25x+2.5y+4z+3t=0.5", "0.25x+42y+3.1z+0t=1.33", "4.2x+11y+0z+3t=1.5", "10x+3.2y+0z+2t=1"}; //size = 4
string row, coefVals;
double coefRow[SIZE], coefB;
int i, j, size;
double det;
double A[SIZE][SIZE], b[SIZE], sol[SIZE];
do{
cout << "Number of Input equations (minimum 1 ~ maximum 5): ";
cin >> size;
} while (size < 1 || size > 5);
cout << "Please, enter the " << size++ << " equations \n"
<< "(Equations to be entered as strings, without spaces)\n";
for (i = 1; i < size; i++){
cin >> row; //
//row=line[i - 1]; // for tests(instead input lines)
Equation(row, coefRow, coefB, coefVals);
for (j = 1; j < size; j++)
A[i][j] = coefRow[j - 1];
b[i] = coefB;
}
cout << "\nA: \n";
for (i = 1; i < size; i++){
for (j = 1; j < size; j++)
cout << A[i][j] << " ";
cout << endl;
}
cout << "\nb: \n";
for (i = 1; i < size; i++)
cout << b[i] << endl;
cout << "\nVariables: \n";
for (i = 1; i < size; i++)
cout << coefVals[i] << endl;
cout << "\nDeterminant= ";
det = Determinant(A, size);
cout << det;
if (det != 0){
Solve(A, b, sol, size);
cout << "\nSolution: \n";
for (i = 1; i < size; i++)
cout << sol[i] << endl;
}
else
cout << "\nSystem has not solution ";
cin.get();
cin.get();
return 0;
}
我的尝试：
这是我的最后一个项目，我无法将其改为c如此困难所以如果任何人可以帮助
What I have tried:
Its my final project and i couldn't change it to c its so difficult so if any one can help
推荐答案
delete
using namespace std;
用printf替换cout
replace "cout" with "printf"
在维基百科中读取兼容性的C和C ++ 文章来理解这个问题。
编译代码并修复编译器错误。最多的是不允许的对象的排序和使用。所以你需要使用char数组......
Read in the wikipedia the Compatibility of C and C++ article to understand that issue.
Compile the code and repair the compiler bugs. The most will be the ordering and the use of objects which arent allowed. So you need to work with char arrays...
看起来像是回到C / C ++基础知识的瓦片。
C编程语言 - 维基百科，免费的百科全书 [ ^ ]
https://hassanolity.files.wordpress.com/2013/11/the_c_programming_language_2.pdf [ ^ ]
http://www.ime.usp.br/~pf/Kernighan-Ritchie/C-Programming-Ebook.pdf [ ^ ]
Looks like it is tile to go back to C/C++ basics.
The C Programming Language - Wikipedia, the free encyclopedia[^]
https://hassanolity.files.wordpress.com/2013/11/the_c_programming_language_2.pdf[^]
http://www.ime.usp.br/~pf/Kernighan-Ritchie/C-Programming-Ebook.pdf[^]
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