This is a code using when decode and encode base64 using c++ hope this help for you

#include “Base64.h”

#include <stdio.h>

const char b64_alphabet[] = “ABCDEFGHIJKLMNOPQRSTUVWXYZ”

“abcdefghijklmnopqrstuvwxyz”

“0123456789+/”;/* ‘Private’ declarations */

inline void a3_to_a4(unsigned char * a4, unsigned char * a3);

inline void a4_to_a3(unsigned char * a3, unsigned char * a4);

inline unsigned char b64_lookup(char c);int base64_encode(char *output, char *input, int inputLen) {

int i = 0, j = 0;

int encLen = 0;

unsigned char a3[3];

unsigned char a4[4];while(inputLen–) {

a3[i++] = *(input++);

if(i == 3) {

a3_to_a4(a4, a3);for(i = 0; i < 4; i++) {

output[encLen++] = b64_alphabet[a4[i]];

}i = 0;

}

}if(i) {

for(j = i; j < 3; j++) {

a3[j] = ”;

}a3_to_a4(a4, a3);

for(j = 0; j < i + 1; j++) {

output[encLen++] = b64_alphabet[a4[j]];

}while((i++ < 3)) {

output[encLen++] = ‘=’;

}

}

output[encLen] = ”;

return encLen;

}int base64_decode(char * output, char * input, int inputLen) {

int i = 0, j = 0;

int decLen = 0;

unsigned char a3[3];

unsigned char a4[4];while (inputLen–) {

if(*input == ‘=’) {

break;

}a4[i++] = *(input++);

if (i == 4) {

for (i = 0; i <4; i++) {

a4[i] = b64_lookup(a4[i]);

}a4_to_a3(a3,a4);

for (i = 0; i < 3; i++) {

output[decLen++] = a3[i];

}

i = 0;

}

}if (i) {

for (j = i; j < 4; j++) {

a4[j] = ”;

}for (j = 0; j <4; j++) {

a4[j] = b64_lookup(a4[j]);

}a4_to_a3(a3,a4);

for (j = 0; j < i – 1; j++) {

output[decLen++] = a3[j];

}

}

output[decLen] = ”;

return decLen;

}int base64_enc_len(int plainLen) {

int n = plainLen;

return (n + 2 – ((n + 2) % 3)) / 3 * 4;

}int base64_dec_len(char * input, int inputLen) {

int i = 0;

int numEq = 0;

for(i = inputLen – 1; input[i] == ‘=’; i–) {

numEq++;

}return ((6 * inputLen) / 8) – numEq;

}inline void a3_to_a4(unsigned char * a4, unsigned char * a3) {

a4[0] = (a3[0] & 0xfc) >> 2;

a4[1] = ((a3[0] & 0x03) << 4) + ((a3[1] & 0xf0) >> 4);

a4[2] = ((a3[1] & 0x0f) << 2) + ((a3[2] & 0xc0) >> 6);

a4[3] = (a3[2] & 0x3f);

}inline void a4_to_a3(unsigned char * a3, unsigned char * a4) {

a3[0] = (a4[0] << 2) + ((a4[1] & 0x30) >> 4);

a3[1] = ((a4[1] & 0xf) << 4) + ((a4[2] & 0x3c) >> 2);

a3[2] = ((a4[2] & 0x3) << 6) + a4[3];

}inline unsigned char b64_lookup(char c) {

if(c >=’A’ && c <=’Z’) return c – ‘A’;

if(c >=’a’ && c <=’z’) return c – 71;

if(c >=’0′ && c <=’9′) return c + 4;

if(c == ‘+’) return 62;

if(c == ‘/’) return 63;

return -1;

}

int main()

{

char input[] =”aaaaaaaa”;

char output[]=””;

int a = base64_encode(output,input,8);

printf(output);

//char *output

return 0;

}