Convert this C++ code to Java code

the code below is to encrypt and decrypt strings of characters using Matrix transposition cipher

#include 

#include 

void cipher(int i, int c); 

int findMin(); 

void makeArray(int, int); 

char arr[22][22], darr[22][22], emessage[111], retmessage[111], key[55]; 

char temp[55], temp2[55]; 

int k = 0; 

int main() 

{ 

 char *message; 

 int i, j, klen, emlen, flag = 0; 

 int r, c, index, rows; 

 printf("Enter the key "); 

 fflush(stdin); 

 gets(key); 

 printf(" Enter message to be ciphered "); 

 fflush(stdin); 

 gets(message); 

 strcpy(temp, key); 

 klen = strlen(key); 

 k = 0; 

 for (i = 0;; i++) 

 { 

 if (flag == 1) 

 break; 

 for (j = 0; key[j] != NULL; j++) 

 { 

 if (message[k] == NULL) 

 { 

 flag = 1; 

 arr[i][j] = '-'; 

 } 

 else 

 { 

 arr[i][j] = message[k++]; 

 } 

 } 

 } 

 r = i; 

 c = j; 

 for (i = 0; i < r; i++) 

 { 

 for (j = 0; j < c; j++) 

 { 

 printf("%c ", arr[i][j]); 

 } 

 printf(" "); 

 } 

 k = 0; 

 for (i = 0; i < klen; i++) 

 { 

 index = findMin(); 

 cipher(index, r); 

 } 

 emessage[k] = '\0'; 

 printf(" Encrypted message is "); 

 for (i = 0; emessage[i] != NULL; i++) 

 printf("%c", emessage[i]); 

 printf("  "); 

 //deciphering 

 emlen = strlen(emessage); 

 //emlen is length of encrypted message 

 strcpy(temp, key); 

 rows = emlen / klen; 

 //rows is no of row of the array to made from ciphered message 

 j = 0; 

 for (i = 0, k = 1; emessage[i] != NULL; i++, k++) 

 { 

 //printf(" Emlen=%d",emlen); 

 temp2[j++] = emessage[i]; 

 if ((k % rows) == 0) 

 { 

 temp2[j] = '\0'; 

 index = findMin(); 

 makeArray(index, rows); 

 j = 0; 

 } 

 } 

 printf(" Array Retrieved is "); 

 k = 0; 

 for (i = 0; i < r; i++) 

 { 

 for (j = 0; j < c; j++) 

 { 

 printf("%c ", darr[i][j]); 

 //retrieving message 

 retmessage[k++] = darr[i][j]; 

 } 

 printf(" "); 

 } 

 retmessage[k] = '\0'; 

 printf(" Message retrieved is "); 

 for (i = 0; retmessage[i] != NULL; i++) 

 printf("%c", retmessage[i]); 

 return (0); 

} 

void cipher(int i, int r) 

{ 

 int j; 

 for (j = 0; j < r; j++) 

 { 

 { 

 emessage[k++] = arr[j][i]; 

 } 

 } 

 // emessage[k]='\0'; 

} 

void makeArray(int col, int row) 

{ 

 int i, j; 

 for (i = 0; i < row; i++) 

 { 

 darr[i][col] = temp2[i]; 

 } 

} 

int findMin() 

{ 

 int i, j, min, index; 

 min = temp[0]; 

 index = 0; 

 for (j = 0; temp[j] != NULL; j++) 

 { 

 if (temp[j] < min) 

 { 

 min = temp[j]; 

 index = j; 

 } 

 } 

 temp[index] = 123; 

 return (index); 

} 

Please make sure that the Java code run on iOS

Thank you