[C++] Vector Matrix

Matrix

 

 

2D vector of doubles

 

 

1)

void print(const vector<vector<double>>& m) {

        for (unsigned row = 0; row < m.size(); row++) {

               for (unsigned col = 0; col < m[row].size(); col++)

                       cout << std::setw(5) << m[row][col];

               cout << '\n';

        }

}

 

2)

void print(const vector<vector<double>>& m) {

        for (const vector<double>& row : m) {

               for (int elem : row)

                       cout << setw(5) << elem;

               cout << '\n';

        }

        return sum;

}

 

3)

using Matrix = vector<vector<double>>;

 

 

void print(const Matrix& m) {

        for (const vector<double>& row : m) {  //for each row

               for (int elem : row)  // for each elem in a row

                       cout << setw(5) << elem;

               cout << '\n';

        }

        return sum;

}

 

---

 

int main() {

        vector<vector<int>> vec{ {1,2,3},

        {4,5,6} };//2 by 3 matrix

       

 

        for (vector<int>& row : vec) { // 행에 대한 값

               for (int& elem : row) // 행의 elem 값

                       cin >> elem;

        }

       

        for (int row = 0; row < vec.size(); row++) {

               for (int col = 0; col < vec[row].size(); col++) {

                       cout << vec[row][col] << '\t';

               }

               cout << endl;

        }

        return 0; 

}

---

 

void print(int* m, int nRow, int nCol) {

        for (int row = 0; row < nRow; row++) {

               for (int col = 0; col < nCol; col++) {

                       cout << m[row][col] << '\t';

               }

               cout << endl;

        }

}

int main() {

        int matrix[2][2] = { {1,2},

                                              {3,4} };  // 정적 2차원 배열

        

        int nRow = 2, nCol = 2;

        int** matrix2;

        matrix2 = new int* [nRow];

        for (int i = 0; i < nRow; i++)

               matrix2[i] = new int[nCol];

        matrix2[0][0] = 1; matrix2[0][1] = 2;

        matrix2[1][0] = 3; matrix2[1][1] = 4;

        print(matrix2, nRow, nCol);

        for (int i = 0; i < nRow; i++)

               delete[] matrix2[i];

        delete[] matrix2;

        return 0;

}

 

---

 

문자 Array 형태

 

 

char* ch= "abcd"

실제로는 5바이트로 저장된다.-> null문자를 만날때까지 서치하는 형태로 할수있다.

a

b

c

d

'\0'  : null문자

bool find_char(const char* s, char ch) {

        while (*s != '\0') { //'\0' == NULL

               if (*s == ch)

                       return true;

               s++;

        }

        return false;

}

int main() {

        const char* phrase = "this is a phrase";

        

        for (char ch = 'a'; ch < 'z'; ch++) { // ascii 코드 형태이기 때문에 사용가능

               cout << ch << " is ";

               if (!find_char(phrase, ch))

                       cout << "NOT";

               cout << "in(" << phrase << ")" << endl;

        }

        return 0;

}

 

 

>>>

a is in(this is a phrase)

b is NOTin(this is a phrase)

c is NOTin(this is a phrase)

d is NOTin(this is a phrase)

e is in(this is a phrase)

f is NOTin(this is a phrase)

g is NOTin(this is a phrase)

h is in(this is a phrase)

i is in(this is a phrase)

j is NOTin(this is a phrase)

k is NOTin(this is a phrase)

l is NOTin(this is a phrase)

m is NOTin(this is a phrase)

n is NOTin(this is a phrase)

o is NOTin(this is a phrase)

p is in(this is a phrase)

q is NOTin(this is a phrase)

r is in(this is a phrase)

s is in(this is a phrase)

t is in(this is a phrase)

u is NOTin(this is a phrase)

v is NOTin(this is a phrase)

w is NOTin(this is a phrase)

x is NOTin(this is a phrase)

y is NOTin(this is a phrase)

 

 

---

 

해당 자료는 경희대학교 소프트웨어융합학과 배성호교수님 수업내용을 참조하였습니다.