Exuting AT commands on an sim800l

Projects Networking, Protocols, and Devices
1

hi

i want to manipulate a sim800l without api,when i excute AT commands directly every thing is fine but when using the code below its not working,whats the wrong with the code

#include <SoftwareSerial.h>
#include <String.h>
//SIM800 TX is connected to Arduino D8
#define SIM800_TX_PIN 7

//SIM800 RX is connected to Arduino D7
#define SIM800_RX_PIN 8
boolean demander_solde;
char reponce[200];
//Create software serial object to communicate with SIM800
SoftwareSerial sim800l(SIM800_TX_PIN, SIM800_RX_PIN);

void setup() {
  // put your setup code here, to run once:
  Serial.begin(4800);
  while (!Serial);
  sim800l.begin(9600);
  while (!sim800l);
  delay(2000);
  demander_solde = true;
  
}

void demanderSolde(){
  char ch; 
  int i=0;
  Serial.write("exec:sim800l.println(\"AT+CUSD=2\");");  
    delay(2000);

  sim800l.println("AT+CUSD=2");
 

 while (!sim800l.available()>0);
 while ((int)ch!=43)
{if(ch=sim800l.read());reponce[i]==ch;i++;Serial.write((int)ch);}
 Serial.write(reponce);    
  delay(2000);

/*  while (!sim800l.available()>0);
  while (ch!=43) {ch=sim800l.read();reponce[i]==ch;i++;}
 Serial.write(reponce);    */

 delay(2000);
 clearReponce(i);
 i=0;

  Serial.write("exec:sim800l.println(\"AT+CUSD=1\");");  
      delay(2000);

  sim800l.println("AT+CUSD=1");  
  while (!sim800l.available()>0);
  while ((int)ch!=43){
  if(ch=sim800l.read());reponce[i]==ch;i++;
  Serial.write((int)ch); 
  }
  
 Serial.write(reponce);   
 delay(2000);
 /*while (!sim800l.available()>0);
 while (ch!=43){ch=sim800l.read();reponce[i]==ch;i++;}
 Serial.write(reponce);*/    
  delay(2000);

  clearReponce(i);
  i=0;
 Serial.write("exec:sim800l.println(\"AT+CUSD=1,\"*222#\"\");");  
     delay(2000);

 sim800l.println("AT+CUSD=1,\"*222#\"");  

 while (!sim800l.available()>0);
 while ((int)ch!=43){
 if(ch=sim800l.read());reponce[i]==ch;Serial.write(reponce);i++;
 Serial.write((int)ch);  
 }
Serial.write(reponce);
delay(2000);
/*while (!sim800l.available()>0) 
while (ch!=43){
 {ch=sim800l.read();reponce[i]==ch;i++;}
 Serial.write(reponce);   
} */
  delay(2000);

 clearReponce(i);
  demander_solde=false;  

}


void clearReponce(int _i){ 
  for(int i=0;i==_i;i++){reponce[i]==0;}
  Serial.println("reponce:");

  Serial.write(reponce);
    delay(2000);


}

void loop() {
  if(demander_solde){
    demanderSolde();
    }
}