Thread: segmentation fault

I have made a temperature conversion problem. everything works except for one bit of programming. I am suppose to account for the segmentation fault if someone only enters one command line argument.
correct way to enter: ./a.out 134 F
segmentation fault enter: ./a.out 134
its suppose to display, "You must enter two arguments" but it just displays segmentation fault. It can only be If statements, and the fault is with my first if statement. Heres my program:

Code:

#include <iostream> // cout
#include <cstdlib> // atoi
#include <iomanip> // fixed, setprecision

using namespace std;

int main(int argc, char *argv[]) {
     float temp, degrees, F_C, F_K, C_F, C_K, K_C, K_F;
     char temp_type;

     temp = atoi(argv[1]); 
     temp_type = *argv[2]; // conversion of temperature type to char
 
     F_C = (temp - 32) * 5/9; // fahrenheit to celsius
     F_K = (temp + 459.67) * 5/9; // fahrenheit to kelvin
     C_F = temp * 9/5 + 32; // celsius to fahrenheit
     C_K = temp + 273.15; // celsius to kelvin
     K_C = temp - 273.15; // kelvin to celsius
     K_F = temp * 9/5 - 459.67; // kelvin to fahrenheit
    
     cout << fixed << setprecision(1);
     if (argc != 3) {
          cout << "You must enter two arguments." << endl;
          return 1;
     } 
     // displays converted temps of Fahrenheit to celcius and kelvin 
     if (temp_type == 'F') {
          cout << temp << "F is " << F_C << "C and " << F_K << "K" << endl;
     }

     // displays converted temps of Celcius to fahrenheit to kelvin
     if (temp_type == 'C') {
          cout << temp << "C is " << C_F << "F and " << C_K << "K" << endl;
     }

     // displays converted temps of Kelvin to fahrenheit and celsius
     if (temp_type == 'K') {
          cout << temp << "K is " << K_F << "F and " << K_C << "C" << endl;
     }

     // displays fault if wrong temperature type is entered
     if ((temp_type != 'F') && (temp_type != 'C') && (temp_type != 'K')) {
          cout << temp_type << " is not valid temperature type." << endl;
     }
     
     cout << "$" << endl;

     return 0;     
}