I'm trying to make a simple program in C that takes these arguments: math.exe (first number) (math operator, like +, -, etc)(second number). The program compiles fine but, doesn't work at all. Here's my source code: #include (stdio.h) #include (stdlib.h) int main(int argc, char *argv[]) { float num1, num2, answer; while(argc < 3) { printf("\n\nUSAGE: add <first number> <operator> <second number>\n\n"); exit(1); } num1 = atof(argv[1]); num2 = atof(argv[2]); if(argv[3] == "+") { answer = num1 + num2; printf("%f + %f = %f",num1,num2,answer); } else if(argv[2] == "-") { answer = num1 - num2; printf("%f - %f = %f",num1,num2,answer); } else if(argv[2] == "/") { answer = num1 / num2; printf("%f / %f = %f",num1,num2,answer); } return 0; }

Hi, you need to use if(strcmp(argv[3],"+")==0) instead of == operator. Here is the working program: #include <stdio.h> #include <stdlib.h> #include <string.h> int main(int argc, char *argv[]) { float num1, num2, answer; while(argc < 3) { printf("\n\nUSAGE: add <first number> <second number> <operator>\n\n"); exit(1); } num1 = atof(argv[1]); num2 = atof(argv[2]); if(strcmp(argv[3],"+")==0) { answer = num1 + num2; printf("%f + %f = %f",num1,num2,answer); } else if(strcmp(argv[3],"-")==0) { answer = num1 - num2; printf("%f - %f = %f",num1,num2,answer); } else if(strcmp(argv[3],"/")==0) { answer = num1 / num2; printf("%f / %f = %f",num1,num2,answer); } else { printf("\n\nUSAGE: add <first number> <second number> <operator>\n\n"); exit(1); } return 0; } -- mohameda@ieee.org

Oh, I see now! I forgot that the elements stored in argv were strings. Thank you very much for the help!

printf("\n\nUSAGE: add <first number> <operator> <second number>\n\n"); num2 = atof(argv[2]); if(strcmp(argv[3],"+")==0) Hmm.... BlueRaja.admin@gmail.com