# Calculator program that performs log, square root, and arithmatic operations

```#include<stdio.h>                        //INCLUDING HEADER FILES
#include<math.h>                        //THIS ONE FOR MATHEMATICAL FUNCTIONS

{
float a,b;
printf("ENTER THE TWO NO. TO BE ADDED::n");
scanf("%f%f",&a,&b);
printf("RESULT:: %f+%f=%fn",a,b,a+b);
}

void subtract()                            //FUNCTION TO PERFORM SUBTRACTION
{
float a,b;
printf("n ENTER THE NUMBERS (a-b) (a FIRST)::n");
scanf("%f%f",&a,&b);
printf("n RESULT:: %f-%f=%fn",a,b,a-b);
}

void multiply()                            //FUNCTION TO PERFORM MULTIPLICATION
{
float a,b;
printf("n ENTER THE TWO NO. TO BE MULTIPLIED::n");
scanf("%f%f",&a,&b);
printf("n RESULT::%f*%f=%fn",a,b,a*b);
}

void divide()                            //FUNCTION TO PERFORM DIVISION
{
float a,b;
printf("n ENTER THE NUMBERS (a/b) (a FIRST)::n");
scanf("%f%f",&a,&b);
while(b==0)
{    printf("n DENOMINATOR CAN'T BE ZERO,  RE-ENTER b::");
scanf("%f",&b);
}
printf("n RESULT:: %f/%f=%fn",a,b,a/b);
}

void inverse()                            //FUNCTION TO PERFORM REVERSING
{
float a;
printf("n ENTER THE NO. TO BE REVERSED::n");
scanf("%f",&a);
while(a==0)
{       printf("n THE NUMBER CAN'T BE ZERO,  RE-ENTER IT::");
scanf("%f",&a);
}
printf("n RESULT:: 1/%f=%fn",a,1/a);
}

void logbe()                            //FUNCTION TO FIND LOG BASE e
{
float a;
printf("n ENTER THE NO. WHOSE Ln IS TO BE CALCULATED::n");
scanf("%f",&a);
while(a<=0)
{       printf("n THE NUMBER SHOULD BE POSITIVE ,  RE-ENTER IT::");
scanf("%f",&a);
}
printf("n RESULT:: ln(%f)=%fn",a,log(a));
}

void logb10()                            //FUNCTION TO FIND LOG BASE 10
{
float a;
printf("n ENTER THE NO. WHOSE LOG IS TO BE CALCULATED::n");
scanf("%f",&a);
while(a<=0)
{       printf("n THE NUMBER SHOULD BE POSITIVE ,  RE-ENTER IT::");
scanf("%f",&a);
}
printf("n RESULT:: log(%f)=%fn",a,log(a)/log(10));
}

void sqroot()                            //FUNCTION TO PERFORM SQUQRE ROOT
{
float a;
printf("n ENTER THE NO. WHOSE SQUARE ROOT IS TO BE CALCULATED::n");
scanf("%f",&a);
while(a<=0)
{       printf("n THE NUMBER SHOULD BE POSITIVE ,  RE-ENTER IT::");
scanf("%f",&a);
}
printf("n RESULT:: SQUARE ROOT OF %f = %fn",a,log(a)/log(10));
}

main()                                //MAIN() STARTS HERE
{
int choice;
do{
printf(" 2.  SUBTRACTIONn");
printf(" 3.  MULTIPLICATIONn");
printf(" 4.  DIVISIONn");
printf(" 5.  INVERSEn");
printf(" 6.  LOG (BASE e)n");
printf(" 7.  LOG (BASE 10)n");
printf(" 8.  SQUARE ROOTn");
printf(" 9.  EXITn");
scanf("%d",&choice);
switch(choice)
{
break;
case 2: subtract();
break;
case 3:    multiply();
break;
case 4: divide();
break;
case 5: inverse();
break;
case 6: logbe();
break;
case 7: logb10();
break;
case 8: sqroot();
break;
case 9: printf("n BYEn");
break;
default:printf("nWRONG CHOICE");
choice=0;
}
}while(!choice);
}

```