Поместить в одномерный массив числа от 1 до 30 (31). И показать календарь на текущий месяц.

int month;
do {

cout << "Enter number of month(1-12):";
cin >> month;

} while (month < 1 || month > 12);
cout << "Mo\tTu\tWe\tTh\tFr\tSa\tSu" << endl;
switch (month) {
case 1:{

int A[31]{};
for (int i = 1; i <= 31; i++)

A[i - 1] = i;

for (int i = 0; i < 35; i++) {

if (i < 4) {

cout << "\t";
continue;

}
cout << A[i - 4] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

case 2:{

int A[29]{};
for (int i = 1; i <= 29; i++)

A[i - 1] = i;

for (int i = 0; i <29; i++) {

cout << A[i] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

case 3: {

int A[31]{};
for (int i = 1; i <= 31; i++)

A[i - 1] = i;

for (int i = 0; i < 32; i++) {

if (i == 0) {

cout << "\t";
continue;

}
cout << A[i - 1] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

case 4: {

int A[30]{};
for (int i = 1; i <= 30; i++)

A[i - 1] = i;

for (int i = 0; i < 34; i++) {

if (i < 4) {

cout << "\t";
continue;

}
cout << A[i - 4] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

case 5: {

int A[31]{};
for (int i = 1; i <= 31; i++)

A[i - 1] = i;

for (int i = 0; i < 37; i++) {

if (i < 6) {

cout << "\t";
continue;

}
cout << A[i - 6] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

case 6: {

int A[30]{};
for (int i = 1; i <= 30; i++)

A[i - 1] = i;

for (int i = 0; i < 32; i++) {

if (i < 2) {

cout << "\t";
continue;

}
cout << A[i - 2] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

case 7: {

int A[31]{};
for (int i = 1; i <= 31; i++)

A[i - 1] = i;

for (int i = 0; i < 35; i++) {

if (i < 4) {

cout << "\t";
continue;

}
cout << A[i - 4] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

case 8: {

int A[31]{};
for (int i = 0; i < 31; i++) {

A[i - 1] = i+1;
cout << A[i-1] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

case 9: {

int A[30]{};
for (int i = 1; i <= 30; i++)

A[i - 1] = i;

for (int i = 0; i < 33; i++) {

if (i < 3) {

cout << "\t";
continue;

}
cout << A[i - 3] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

case 10: {

int A[31]{};
for (int i = 1; i <= 31; i++)

A[i - 1] = i;

for (int i = 0; i < 36; i++) {

if (i < 5) {

cout << "\t";
continue;

}
cout << A[i - 5] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

case 11: {

int A[30]{};
for (int i = 1; i <= 30; i++)

A[i - 1] = i;

for (int i = 0; i < 31; i++) {

if (i==0) {

cout << "\t";
continue;

}
cout << A[i - 1] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

case 12: {

int A[31]{};
for (int i = 1; i <= 31; i++)

A[i - 1] = i;

for (int i = 0; i < 34; i++) {

if (i < 3) {

cout << "\t";
continue;

}
cout << A[i - 3] << "\t";
if ((i + 1) % 7 == 0)

cout << endl;

}
cout << endl;

}
break;

}
system("pause");