Receive blank message

I am new in this field as Embedded Engineer specially for IOT Domain. i want, i write some text on arduino’s serial monitor and that message received on mobile number but i received blank message. SIM details: Location: India. Operator: Airtel i know basic about c, c++, arduino

#include <SoftwareSerial.h>
SoftwareSerial sim(3,2);

void setup() {
delay(5000); //delay for 7 seconds to make sure the modules get the signal
Serial.begin(9600);
Serial.println(“System Started…”);
sim.begin(9600);
delay(1000);
}

void loop() {
if (Serial.available() > 0)

if(Serial.read())
{
char txtMsg[200];
readSerial(txtMsg);
Serial.println(txtMsg);
SendMessage();
}

if (sim.available() > 0)
Serial.write(sim.read());
}

void SendMessage()
{
String txtMsg;
sim.println(“AT+CMGF=1”); //Sets the GSM Module in Text Mode
delay(1000);
sim.println(“AT+CMGS=”+91xxxxxxxxxxx"\r"); //Mobile phone number to send message
delay(1000);
sim.println(txtMsg);
delay(100);
sim.println((char)26);// ASCII code of CTRL+Z
delay(1000);
}

int readSerial(char result[]) {
int i = 0;
while (1) {
while (Serial.available() > 0) {
char inChar = Serial.read();
if (inChar == ‘\n’) {
result[i] = ‘\0’;
Serial.flush();
return 0;
}
if (inChar != ‘\r’) {
result[i] = inChar;
i++;
}
}
}
}